diff --git a/bin/commandInstall.ml b/bin/commandInstall.ml
index 3a9d105..d2c80a4 100644
--- a/bin/commandInstall.ml
+++ b/bin/commandInstall.ml
@@ -13,7 +13,7 @@ let transitive_closure map =
     | None -> visited
     | Some cur ->
       match Map.find map cur with
-      | None -> failwithf "Packages %s is not found\n" cur ();
+      | None -> failwithf "Library %s is not found\n" cur ();
       | Some nexts ->
         let visited = StringSet.add visited cur in
         let queue =  StringSet.union (StringSet.remove queue cur) (StringSet.diff nexts visited) in
@@ -22,98 +22,98 @@ let transitive_closure map =
 
 
 (* TODO Install transitive dependencies *)
-let get_packages ~reg ~reg_opam ~packages =
-  let dist_package_dir = SatysfiDirs.satysfi_dist_dir () in
-  Printf.printf "Reading runtime dist: %s\n" dist_package_dir;
-  let dist_package = Package.read_dir dist_package_dir in
-  let user_packages = Registry.list reg
+let get_libraries ~reg ~reg_opam ~libraries =
+  let dist_library_dir = SatysfiDirs.satysfi_dist_dir () in
+  Printf.printf "Reading runtime dist: %s\n" dist_library_dir;
+  let dist_library = Library.read_dir dist_library_dir in
+  let user_libraries = Registry.list reg
     |> StringSet.of_list
     |> StringSet.to_map ~f:(Registry.directory reg)
   in
-  Printf.printf "Read user packages: %s\n" (user_packages |> Map.keys |> [%sexp_of: string list] |> Sexp.to_string_hum);
-  let opam_packages = match reg_opam with
+  Printf.printf "Read user libraries: %s\n" (user_libraries |> Map.keys |> [%sexp_of: string list] |> Sexp.to_string_hum);
+  let opam_libraries = match reg_opam with
     | None -> StringSet.to_map StringSet.empty ~f:ident
     | Some reg_opam ->
         SatysfiRegistry.list reg_opam
         |> StringSet.of_list
         |> StringSet.to_map ~f:(SatysfiRegistry.directory reg_opam)
   in
-  Printf.printf "Reading opam packages: %s\n" (opam_packages |> Map.keys |> [%sexp_of: string list] |> Sexp.to_string_hum);
-  let all_packages =
-    Map.merge opam_packages user_packages ~f:(fun ~key -> function
-      | `Left x -> Package.read_dir x |> Some
-      | `Right x -> Package.read_dir x |> Some
+  Printf.printf "Reading opam libraries: %s\n" (opam_libraries |> Map.keys |> [%sexp_of: string list] |> Sexp.to_string_hum);
+  let all_libraries =
+    Map.merge opam_libraries user_libraries ~f:(fun ~key -> function
+      | `Left x -> Library.read_dir x |> Some
+      | `Right x -> Library.read_dir x |> Some
       | `Both (_, x) ->
-        Printf.printf "Package %s is provided by both the user local and opam repositories\n" key;
-        Package.read_dir x |> Some) in
-  let required_packages = match packages with
-    | None -> all_packages
-    | Some packages -> let package_dependency =
-          Map.map all_packages ~f:(fun p -> p.Package.dependencies) in
-        let packages_to_install = transitive_closure package_dependency (StringSet.of_list packages) in
-        Map.filter_keys all_packages ~f:(StringSet.mem packages_to_install)
+        Printf.printf "Library %s is provided by both the user local and opam repositories\n" key;
+        Library.read_dir x |> Some) in
+  let required_libraries = match libraries with
+    | None -> all_libraries
+    | Some libraries -> let library_dependency =
+          Map.map all_libraries ~f:(fun p -> p.Library.dependencies) in
+        let libraries_to_install = transitive_closure library_dependency (StringSet.of_list libraries) in
+        Map.filter_keys all_libraries ~f:(StringSet.mem libraries_to_install)
   in
-  match Map.add required_packages ~key:"dist" ~data:dist_package with
+  match Map.add required_libraries ~key:"dist" ~data:dist_library with
     | `Ok result -> result
     | `Duplicate ->
       Printf.printf "Overriding dist with user installed one";
-      required_packages
+      required_libraries
 
-let install d ~system_font_prefix ~packages ~verbose ~copy () =
+let install d ~system_font_prefix ~libraries ~verbose ~copy () =
   (* TODO build all *)
-  Printf.printf "Updating packages\n";
+  Printf.printf "Updating libraries\n";
   begin match Repository.update_all repo with
-  | Some updated_packages -> begin
-    Printf.printf "Updated packages: ";
-    [%derive.show: string list] updated_packages |> print_endline
+  | Some updated_libraries -> begin
+    Printf.printf "Updated libraries: ";
+    [%derive.show: string list] updated_libraries |> print_endline
   end
   | None ->
-    Printf.printf "No packages updated\n"
+    Printf.printf "No libraries updated\n"
   end;
-  Printf.printf "Building updated packages\n";
+  Printf.printf "Building updated libraries\n";
   begin match Registry.update_all reg with
-  | Some updated_packages -> begin
-    Printf.printf "Built packages: ";
-    [%derive.show: string list] updated_packages |> print_endline
+  | Some updated_libraries -> begin
+    Printf.printf "Built libraries: ";
+    [%derive.show: string list] updated_libraries |> print_endline
   end
   | None ->
-    Printf.printf "No packages built\n"
+    Printf.printf "No libraries built\n"
   end;
-  let package_map = get_packages ~reg ~reg_opam ~packages in
-  let packages = package_map |> Map.data in
-  Printf.printf "Installing packages: ";
-  Map.keys package_map |> [%sexp_of: string list] |> Sexp.to_string_hum |> print_endline;
-  let packages = match system_font_prefix with
-    | None -> Printf.printf "Not gathering system fonts\n"; packages
+  let library_map = get_libraries ~reg ~reg_opam ~libraries in
+  let libraries = library_map |> Map.data in
+  Printf.printf "Installing libraries: ";
+  Map.keys library_map |> [%sexp_of: string list] |> Sexp.to_string_hum |> print_endline;
+  let libraries = match system_font_prefix with
+    | None -> Printf.printf "Not gathering system fonts\n"; libraries
     | Some(prefix) ->
       Printf.printf "Gathering system fonts with prefix %s\n" prefix;
-      let systemFontPackage = SystemFontPackage.get_package prefix () in
-      List.cons systemFontPackage packages
+      let systemFontLibrary = SystemFontLibrary.get_library prefix () in
+      List.cons systemFontLibrary libraries
   in
-  let merged = packages
-    |> List.fold_left ~f:Package.union ~init:Package.empty
+  let merged = libraries
+    |> List.fold_left ~f:Library.union ~init:Library.empty
   in
-  match FileUtil.test FileUtil.Is_dir d, Package.is_managed_dir d with
+  match FileUtil.test FileUtil.Is_dir d, Library.is_managed_dir d with
   | true, false ->
     Printf.printf "Directory %s is not managed by Satyrographos.\n" d;
     Printf.printf "Please remove %s first.\n" d
   | _, _ ->
     Printf.printf "Removing destination %s\n" d;
     FileUtil.(rm ~force:Force ~recurse:true [d]);
-    Package.mark_managed_dir d;
+    Library.mark_managed_dir d;
     if verbose
     then begin
-      Printf.printf "Loaded packages\n";
-      [%sexp_of: Package.t list] packages
+      Printf.printf "Loaded libraries\n";
+      [%sexp_of: Library.t list] libraries
       |> Sexp.to_string_hum
       |> print_endline;
       Printf.printf "Installing %s\n" d;
-      [%sexp_of: Package.t] merged
+      [%sexp_of: Library.t] merged
       |> Sexp.to_string_hum
       |> print_endline
     end;
-    Package.write_dir ~symlink:(not copy) d merged;
-    List.iter ~f:(Printf.printf "WARNING: %s") (Package.validate merged);
+    Library.write_dir ~symlink:(not copy) d merged;
+    List.iter ~f:(Printf.printf "WARNING: %s") (Library.validate merged);
     Printf.printf "Installation completed!\n"
 
 let install_command =
@@ -126,14 +126,14 @@ let install_command =
     ~readme
     [%map_open
       let system_font_prefix = flag "system-font-prefix" (optional string) ~doc:"FONT_NAME_PREFIX Installing system fonts with names with the given prefix"
-      and package_list = flag "package" (listed string) ~doc:"PACKAGE Package"
+      and library_list = flag "library" (listed string) ~doc:"LIBRARY Library"
       and target_dir = anon (maybe_with_default default_target_dir ("DIR" %: string))
       and verbose = flag "verbose" no_arg ~doc:"Make verbose"
       and copy = flag "copy" no_arg ~doc:"Copy files instead of making symlinks"
       in
       fun () ->
-        let packages = match package_list with
+        let libraries = match library_list with
           | [] -> None
           | xs -> Some xs in
-        install target_dir ~system_font_prefix ~packages ~verbose ~copy ()
+        install target_dir ~system_font_prefix ~libraries ~verbose ~copy ()
     ]
diff --git a/bin/commandLibrary.ml b/bin/commandLibrary.ml
new file mode 100644
index 0000000..c8eae61
--- /dev/null
+++ b/bin/commandLibrary.ml
@@ -0,0 +1,75 @@
+open Satyrographos
+open Core
+
+open Setup
+
+
+let library_show_command_g p_show =
+  let open Command.Let_syntax in
+  Command.basic
+    ~summary:"Show library information (experimental)"
+    [%map_open
+      let p = anon ("LIBRARY" %: string)
+      in
+      fun () ->
+        p_show p ()
+    ]
+let library_list_command_g p_list =
+  let open Command.Let_syntax in
+  Command.basic
+    ~summary:"Show list of libraries installed (experimental)"
+    [%map_open
+      let _ = args (* ToDo: Remove this *)
+      in
+      fun () ->
+        p_list ()
+    ]
+
+let library_list () =
+  Compatibility.optin ();
+  [%derive.show: string list] (Registry.list reg) |> print_endline
+let library_list_command =
+  library_list_command_g library_list
+
+let library_show p () =
+  Compatibility.optin ();
+  Registry.directory reg p
+    |> Library.read_dir
+    |> [%sexp_of: Library.t]
+    |> Sexp.to_string_hum
+    |> print_endline
+let library_show_command =
+  library_show_command_g library_show
+
+let library_command =
+  Command.group ~summary:"Install libraries (experimental)"
+    [ "list", library_list_command; (* ToDo: use this default*)
+      "show", library_show_command;
+    ]
+
+
+let library_opam_list () =
+  Compatibility.optin ();
+  Option.iter reg_opam ~f:(fun reg_opam ->
+    [%derive.show: string list] (SatysfiRegistry.list reg_opam) |> print_endline
+  )
+let library_opam_list_command =
+  library_list_command_g library_opam_list
+
+let library_opam_show p () =
+  Compatibility.optin ();
+  Option.iter reg_opam ~f:(fun reg_opam ->
+    SatysfiRegistry.directory reg_opam p
+      |> Library.read_dir
+      |> [%sexp_of: Library.t]
+      |> Sexp.to_string_hum
+      |> print_endline
+  )
+let library_opam_show_command =
+  library_show_command_g library_opam_show
+
+let library_opam_command =
+  Command.group ~summary:"Inspect libraries installed in the OPAM managed directory (experimental)"
+    [ "list", library_opam_list_command; (* ToDo: use this default*)
+      "show", library_opam_show_command;
+    ]
diff --git a/bin/commandOpam.ml b/bin/commandOpam.ml
index db55e51..6b7f100 100644
--- a/bin/commandOpam.ml
+++ b/bin/commandOpam.ml
@@ -4,19 +4,19 @@ open Core
 
 module StringMap = Map.Make(String)
 
-let package_dir prefix buildscript =
+let library_dir prefix buildscript =
   let libdir = Filename.concat prefix "share/satysfi" in
   Filename.concat libdir buildscript.BuildScript.name
 
 let install_opam ~verbose ~prefix ~build_module ~buildscript_path =
   let src_dir = Filename.dirname buildscript_path in
-  let p = BuildScript.read_package ~src_dir build_module in
-  if verbose then [%sexp_of: Package.t] p |> Sexp.to_string_hum |> Printf.printf "Read package:\n%s\n";
-  let dir = package_dir prefix build_module in
-  Package.write_dir ~verbose ~symlink:false dir p
+  let p = BuildScript.read_library ~src_dir build_module in
+  if verbose then [%sexp_of: Library.t] p |> Sexp.to_string_hum |> Printf.printf "Read library:\n%s\n";
+  let dir = library_dir prefix build_module in
+  Library.write_dir ~verbose ~symlink:false dir p
 
 let uninstall_opam ~verbose:_ ~prefix ~build_module ~buildscript_path:_ =
-  let dir = package_dir prefix build_module in
+  let dir = library_dir prefix build_module in
   FileUtil.(rm ~force:Force ~recurse:true [dir])
 
 let default_script_path () =
diff --git a/bin/commandPackage.ml b/bin/commandPackage.ml
deleted file mode 100644
index 55ce60d..0000000
--- a/bin/commandPackage.ml
+++ /dev/null
@@ -1,75 +0,0 @@
-open Satyrographos
-open Core
-
-open Setup
-
-
-let package_show_command_g p_show =
-  let open Command.Let_syntax in
-  Command.basic
-    ~summary:"Show package information (experimental)"
-    [%map_open
-      let p = anon ("PACKAGE" %: string)
-      in
-      fun () ->
-        p_show p ()
-    ]
-let package_list_command_g p_list =
-  let open Command.Let_syntax in
-  Command.basic
-    ~summary:"Show list of packages installed (experimental)"
-    [%map_open
-      let _ = args (* ToDo: Remove this *)
-      in
-      fun () ->
-        p_list ()
-    ]
-
-let package_list () =
-  Compatibility.optin ();
-  [%derive.show: string list] (Registry.list reg) |> print_endline
-let package_list_command =
-  package_list_command_g package_list
-
-let package_show p () =
-  Compatibility.optin ();
-  Registry.directory reg p
-    |> Package.read_dir
-    |> [%sexp_of: Package.t]
-    |> Sexp.to_string_hum
-    |> print_endline
-let package_show_command =
-  package_show_command_g package_show
-
-let package_command =
-  Command.group ~summary:"Install packages (experimental)"
-    [ "list", package_list_command; (* ToDo: use this default*)
-      "show", package_show_command;
-    ]
-
-
-let package_opam_list () =
-  Compatibility.optin ();
-  Option.iter reg_opam ~f:(fun reg_opam ->
-    [%derive.show: string list] (SatysfiRegistry.list reg_opam) |> print_endline
-  )
-let package_opam_list_command =
-  package_list_command_g package_opam_list
-
-let package_opam_show p () =
-  Compatibility.optin ();
-  Option.iter reg_opam ~f:(fun reg_opam ->
-    SatysfiRegistry.directory reg_opam p
-      |> Package.read_dir
-      |> [%sexp_of: Package.t]
-      |> Sexp.to_string_hum
-      |> print_endline
-  )
-let package_opam_show_command =
-  package_show_command_g package_opam_show
-
-let package_opam_command =
-  Command.group ~summary:"Inspect packages installed in the OPAM managed directory (experimental)"
-    [ "list", package_opam_list_command; (* ToDo: use this default*)
-      "show", package_opam_show_command;
-    ]
diff --git a/bin/commandPin.ml b/bin/commandPin.ml
index d2bc201..3221395 100644
--- a/bin/commandPin.ml
+++ b/bin/commandPin.ml
@@ -9,7 +9,7 @@ let pin_list () =
 let pin_list_command =
   let open Command.Let_syntax in
   Command.basic
-    ~summary:"List installed packages (experimental)"
+    ~summary:"List installed libraries (experimental)"
     [%map_open
       let _ = args (* ToDo: Remove this *)
       in
@@ -23,9 +23,9 @@ let pin_dir p () =
 let pin_dir_command =
   let open Command.Let_syntax in
   Command.basic
-    ~summary:"Get directory where package PACKAGE is stored (experimental)"
+    ~summary:"Get directory where library LIBRARY is stored (experimental)"
     [%map_open
-      let p = anon ("PACKAGE" %: string)
+      let p = anon ("LIBRARY" %: string)
       in
       fun () ->
         pin_dir p ()
@@ -34,20 +34,20 @@ let pin_dir_command =
 let pin_add p url () =
   Compatibility.optin ();
   Printf.printf "Compatibility warning: Although currently Satyrographos simply copies the given directory,\n";
-  Printf.printf "it will have a build script to control package installation, which is a breaking change.";
+  Printf.printf "it will have a build script to control library installation, which is a breaking change.";
   Uri.of_string url
   |> Repository.add repo p
   |> ignore;
   Printf.printf "Added %s (%s)\n" p url;
   Registry.update_all reg
   |> [%derive.show: string list option]
-  |> Printf.printf "Built packages: %s\n"
+  |> Printf.printf "Built libraries: %s\n"
 let pin_add_command =
   let open Command.Let_syntax in
   Command.basic
-    ~summary:"Add package with name PACKAGE copying from URL (experimental)"
+    ~summary:"Add library with name LIBRARY copying from URL (experimental)"
     [%map_open
-      let p = anon ("PACKAGE" %: string)
+      let p = anon ("LIBRARY" %: string)
       and url = anon ("URL" %: string) (* TODO define Url.t Arg_type.t *)
       in
       fun () ->
@@ -56,22 +56,22 @@ let pin_add_command =
 
 let pin_remove p () =
   Compatibility.optin ();
-  (* TODO remove the package *)
+  (* TODO remove the library *)
   Repository.remove repo p;
   Printf.printf "Removed %s\n" p
 let pin_remove_command =
   let open Command.Let_syntax in
   Command.basic
-    ~summary:"Remove package (experimental)"
+    ~summary:"Remove library (experimental)"
     [%map_open
-      let p = anon ("PACKAGE" %: string) (* ToDo: Remove this *)
+      let p = anon ("LIBRARY" %: string) (* ToDo: Remove this *)
       in
       fun () ->
         pin_remove p ()
     ]
 
 let pin_command =
-  Command.group ~summary:"Manipulate packages (experimental)"
+  Command.group ~summary:"Manipulate libraries (experimental)"
     [ "list", pin_list_command; (* ToDo: use this default*)
       "dir", pin_dir_command;
       "add", pin_add_command;
diff --git a/bin/commandStatus.ml b/bin/commandStatus.ml
index 3a24271..54d1ce4 100644
--- a/bin/commandStatus.ml
+++ b/bin/commandStatus.ml
@@ -9,7 +9,7 @@ let status () =
   [%derive.show: int option] current_scheme_version |> print_endline;
   printf "Source repository: ";
   [%derive.show: string list] (Repository.list repo) |> print_endline;
-  printf "Built package registry: ";
+  printf "Built library registry: ";
   [%derive.show: string list] (Registry.list reg) |> print_endline;
   printf "SATySFi runtime directories: ";
   [%derive.show: string list] (SatysfiDirs.runtime_dirs ()) |> print_endline;
diff --git a/bin/dune b/bin/dune
index 03c9251..2758faf 100644
--- a/bin/dune
+++ b/bin/dune
@@ -3,4 +3,4 @@
  (public_name satyrographos)
  (preprocess (pps ppx_deriving.std ppx_jane))
  (libraries core satyrographos uri)
- (modules setup compatibility commandInstall commandOpam commandPackage commandPin commandStatus main))
+ (modules setup compatibility commandInstall commandLibrary commandOpam commandPin commandStatus main))
diff --git a/bin/main.ml b/bin/main.ml
index 0d75a66..34b4a99 100644
--- a/bin/main.ml
+++ b/bin/main.ml
@@ -5,8 +5,8 @@ let total_command =
   Command.group ~summary:"Simple SATySFi Package Manager"
     [
       "opam", CommandOpam.opam_command;
-      "package", CommandPackage.package_command;
-      "package-opam", CommandPackage.package_opam_command;
+      "library", CommandLibrary.library_command;
+      "library-opam", CommandLibrary.library_opam_command;
       "status", CommandStatus.status_command;
       "pin", CommandPin.pin_command;
       "install", CommandInstall.install_command;
diff --git a/bin/setup.ml b/bin/setup.ml
index a179f61..0592079 100644
--- a/bin/setup.ml
+++ b/bin/setup.ml
@@ -10,18 +10,18 @@ let prefix = match SatysfiDirs.home_dir () with
 let target_dist_dir = Filename.concat prefix ".satysfi"
 let root_dir = Filename.concat prefix ".satyrographos"
 let repository_dir = SatyrographosDirs.repository_dir root_dir
-let package_dir = SatyrographosDirs.package_dir root_dir
+let library_dir = SatyrographosDirs.library_dir root_dir
 let metadata_file = SatyrographosDirs.metadata_file root_dir
 
-let current_scheme_version = Version.get_version root_dir
+let current_scheme_version = SatyrographosDirs.get_scheme_version root_dir
 
 (* TODO Move this to a new module *)
 let initialize () =
   match current_scheme_version with
   | None ->
     Repository.initialize repository_dir metadata_file;
-    Registry.initialize package_dir metadata_file;
-    Version.mark_version root_dir scheme_version
+    Registry.initialize library_dir metadata_file;
+    SatyrographosDirs.mark_scheme_version root_dir scheme_version
   | Some 0 -> Printf.sprintf "Semantics of `pin add` has been changed.\nPlease remove %s to continue." root_dir |> failwith
   | Some 1 -> ()
   | Some v -> Printf.sprintf "Unknown scheme version %d" v |> failwith
@@ -32,11 +32,11 @@ let () =
 (* Source repository *)
 let repo = Repository.read repository_dir metadata_file
 (* Binary registry *)
-let reg = Registry.read package_dir repo metadata_file
+let reg = Registry.read library_dir repo metadata_file
 let reg_opam =
   SatysfiDirs.opam_share_dir ()
   |> Option.map ~f:(fun opam_share_dir ->
-      {SatysfiRegistry.package_dir=Filename.concat opam_share_dir "satysfi"})
+      SatysfiRegistry.read (Filename.concat opam_share_dir "satysfi"))
 
 let default_target_dir =
   Sys.getenv "SATYSFI_RUNTIME"
diff --git a/src/SatyrographosDirs.ml b/src/SatyrographosDirs.ml
deleted file mode 100644
index 5a86195..0000000
--- a/src/SatyrographosDirs.ml
+++ /dev/null
@@ -1,7 +0,0 @@
-open Core
-
-let repository_dir sg_dir = Filename.concat sg_dir "repo"
-let package_dir sg_dir = Filename.concat sg_dir "packages"
-let metadata_file sg_dir = Filename.concat sg_dir "metadata"
-
-let current_scheme_version sg_dir = Version.get_version sg_dir
diff --git a/src/buildScript.ml b/src/buildScript.ml
index 727c5fe..9fff3bd 100644
--- a/src/buildScript.ml
+++ b/src/buildScript.ml
@@ -57,10 +57,10 @@ type package = {
   name: string;
   opam: string;
   sources: sources [@sexp.omit_nil];
-  dependencies: Package.Dependency.t [@sexp.omit_nil];
+  dependencies: Library.Dependency.t [@sexp.omit_nil];
 } [@@deriving sexp]
 
-type section = Package of {
+type section = Library of {
   name: string;
   opam: string;
   sources: source list
@@ -82,14 +82,14 @@ let input ch =
   let sexp = Sexp.input_sexps ch in
   let modules = sexp |> List.concat_map ~f:(fun sexp ->
     match [%of_sexp: section] sexp with
-    | Package {name; opam; sources; dependencies} ->
+    | Library {name; opam; sources; dependencies} ->
       let sources = List.fold_left ~init:empty_sources ~f:begin fun acc -> function
         | File (dst, src) -> add_files dst src acc
         | Font (dst, src) -> add_fonts dst src acc
         | Hash (dst, src) -> add_hashes dst src acc
         | Package (dst, src) -> add_packages dst src acc
       end sources in
-      let dependencies = List.map dependencies ~f:fst |> Package.Dependency.of_list in
+      let dependencies = List.map dependencies ~f:fst |> Library.Dependency.of_list in
       [{name; opam; sources; dependencies}]
   ) in
   List.map ~f:(fun m -> m.name, m) modules
@@ -112,18 +112,18 @@ let export_opam_package p =
 let export_opam bs =
   StringMap.iter bs ~f:export_opam_package
 
-let read_package p ~src_dir =
+let read_library p ~src_dir =
   let map_file dst_dir = List.map ~f:(fun (dst, src) -> (Filename.concat dst_dir dst, Filename.concat src_dir src)) in
   let other_files = map_file "" p.sources.files in
   let hashes =
     map_file "hash" p.sources.hashes
-    |> List.fold ~init:Package.empty ~f:(fun a (dst, src) -> Package.add_hash dst src a)
+    |> List.fold ~init:Library.empty ~f:(fun a (dst, src) -> Library.add_hash dst src a)
   in
   let fonts = map_file (Filename.concat "fonts" p.name) p.sources.fonts in
   let packages = map_file (Filename.concat "packages" p.name) p.sources.packages in
-  Package.{
-   files=List.concat [other_files; fonts; packages] |> Package.PackageFiles.of_alist_exn;
-   hashes=PackageFiles.empty;
+  Library.{
+   files=List.concat [other_files; fonts; packages] |> Library.LibraryFiles.of_alist_exn;
+   hashes=LibraryFiles.empty;
    dependencies=p.dependencies;
   }
-  |> Package.union hashes
+  |> Library.union hashes
diff --git a/src/package.ml b/src/library.ml
similarity index 89%
rename from src/package.ml
rename to src/library.ml
index ac255c5..8e410d8 100644
--- a/src/package.ml
+++ b/src/library.ml
@@ -1,6 +1,6 @@
 open Core
 
-module PackageFiles = struct
+module LibraryFiles = struct
   include Map.Make(String)
 
   let union f = merge ~f:(fun ~key:key -> function
@@ -23,15 +23,15 @@ module StringMap = Map.Make(String)
 module JsonSet = Set.Make(Json)
 
 type t = {
-  hashes: (string list * Json.t) PackageFiles.t;
-  files: string PackageFiles.t;
+  hashes: (string list * Json.t) LibraryFiles.t;
+  files: string LibraryFiles.t;
   dependencies: Dependency.t;
 }
 [@@deriving sexp, compare]
 
 let empty = {
-  hashes = PackageFiles.empty;
-  files = PackageFiles.empty;
+  hashes = LibraryFiles.empty;
+  files = LibraryFiles.empty;
   dependencies = Dependency.empty;
 }
 
@@ -70,9 +70,9 @@ let validate_hash f abs_fs = function
   | _ -> [f ^ " is not an object. Originally from " ^ show_file_list abs_fs]
 
 let validate p =
-  PackageFiles.mapi p.hashes
+  LibraryFiles.mapi p.hashes
     ~f:(fun ~key:f ~data:(abs_fs, h) -> validate_hash f abs_fs h)
-  |> PackageFiles.data
+  |> LibraryFiles.data
   |> List.concat
 
 let normalize_hash = function
@@ -90,7 +90,7 @@ let normalize_hash = function
       j
 
 let normalize p = {
-  hashes = PackageFiles.map p.hashes ~f:(fun (paths, json) -> paths, normalize_hash json);
+  hashes = LibraryFiles.map p.hashes ~f:(fun (paths, json) -> paths, normalize_hash json);
   files = p.files;
   dependencies = p.dependencies;
 }
@@ -98,11 +98,11 @@ let normalize p = {
 let add_file f absolute_path p =
   if FilePath.is_relative absolute_path
   then failwith ("BUG: FilePath must be absolute but got " ^ absolute_path)
-  else { p with files = PackageFiles.add_exn ~key:f ~data:absolute_path p.files }
+  else { p with files = LibraryFiles.add_exn ~key:f ~data:absolute_path p.files }
 
 let add_hash f abs_f p =
   let json = Json.from_file abs_f in
-  { p with hashes = PackageFiles.add_exn ~key:f ~data:([abs_f], json) p.hashes }
+  { p with hashes = LibraryFiles.add_exn ~key:f ~data:([abs_f], json) p.hashes }
 
 let union p1 p2 =
   let handle_file_conflict f f1 f2 = match FileUtil.cmp f1 f2 with
@@ -114,8 +114,8 @@ let union p1 p2 =
     | `Assoc a1, `Assoc a2 -> Some(List.append f1 f2, `Assoc (List.append a1 a2)) (* TODO: Handle conflicting cases*)
     | _, _ -> failwith ("Conflicting file " ^ f ^ "\n  " ^ show_file_list f1 ^ "\n and \n  " ^ show_file_list f2)
   in
-  { hashes = PackageFiles.union handle_hash_conflict p1.hashes p2.hashes;
-    files = PackageFiles.union handle_file_conflict p1.files p2.files;
+  { hashes = LibraryFiles.union handle_hash_conflict p1.hashes p2.hashes;
+    files = LibraryFiles.union handle_file_conflict p1.files p2.files;
     dependencies = Dependency.union p1.dependencies p2.dependencies
   }
 
@@ -160,12 +160,12 @@ let read_dir d =
   in
   if FileUtil.test FileUtil.Is_dir d
   then FileUtil.(find ~follow:Follow Is_file d add empty)
-  else failwith (d ^ " is not a package directory")
+  else failwith (d ^ " is not a library directory")
 
 let write_dir ?(verbose=false) ?(symlink=false) d p =
   let p = normalize p in
   FileUtil.mkdir ~parent:true d;
-  PackageFiles.iteri ~f:(fun ~key:path ~data:fullpath ->
+  LibraryFiles.iteri ~f:(fun ~key:path ~data:fullpath ->
     let file_dst = FilePath.concat d path in
     let action = if symlink
       then "Linking"
@@ -185,7 +185,7 @@ let write_dir ?(verbose=false) ?(symlink=false) d p =
       UnixLabels.symlink ~to_dir:false ~src:fullpath ~dst:file_dst
     else FileUtil.cp [fullpath] file_dst
   ) p.files;
-  PackageFiles.iteri ~f:(fun ~key:path ~data:(_, h) ->
+  LibraryFiles.iteri ~f:(fun ~key:path ~data:(_, h) ->
     let file_dst = FilePath.concat d path in
     begin if verbose
       then Printf.printf "Generating %s\n" file_dst
diff --git a/src/metadata.ml b/src/metadata.ml
index eabe9cd..027b67f 100644
--- a/src/metadata.ml
+++ b/src/metadata.ml
@@ -7,22 +7,22 @@ module Uri_sexp = struct
   let compare = Uri.compare
 end
 
-type package_name = string
-exception RegisteredAlready of package_name
+type library_name = string
+exception RegisteredAlready of library_name
 
-module Packages = String.Map
+module Libraries = String.Map
 type entry = {
   url: Uri_sexp.t;
 } [@@deriving sexp]
 
 type t = {
-  packages: entry Packages.t;
+  libraries: entry Libraries.t;
 } [@@deriving sexp]
 
 type store = string
 
 let empty = {
-  packages = Packages.empty;
+  libraries = Libraries.empty;
 }
 
 let initialize file =
@@ -42,15 +42,15 @@ let with_modifying_file file ~f =
   |> [%sexp_of: t]
   |> Sexp.save_hum file
 
-let list reg = with_reading_file reg ~f:(fun m -> Packages.keys m.packages)
-let find reg name = with_reading_file reg ~f:(fun m -> Packages.find m.packages name)
-let mem reg name = with_reading_file reg ~f:(fun m -> Packages.mem m.packages name)
-let remove reg name = with_modifying_file reg ~f:(fun m -> {packages = Packages.remove m.packages name})
+let list reg = with_reading_file reg ~f:(fun m -> Libraries.keys m.libraries)
+let find reg name = with_reading_file reg ~f:(fun m -> Libraries.find m.libraries name)
+let mem reg name = with_reading_file reg ~f:(fun m -> Libraries.mem m.libraries name)
+let remove reg name = with_modifying_file reg ~f:(fun m -> {libraries = Libraries.remove m.libraries name})
 let remove_multiple reg names =
   let name_set = String.Set.of_list names in
   with_modifying_file reg ~f:(fun m ->
-    {packages = Packages.filter_keys ~f:(Fn.compose (not) (String.Set.mem name_set)) m.packages}
+    {libraries = Libraries.filter_keys ~f:(Fn.compose (not) (String.Set.mem name_set)) m.libraries}
   )
-let add reg name ent = with_modifying_file reg ~f:(fun m -> {packages = Packages.add_exn m.packages ~key:name ~data:ent})
+let add reg name ent = with_modifying_file reg ~f:(fun m -> {libraries = Libraries.add_exn m.libraries ~key:name ~data:ent})
 
 (* Tests *)
diff --git a/src/registry.ml b/src/registry.ml
index dff0f8d..dfd2930 100644
--- a/src/registry.ml
+++ b/src/registry.ml
@@ -1,7 +1,7 @@
 open Core
 
-type package_name = string
-exception RegisteredAlready of package_name
+type library_name = string
+exception RegisteredAlready of library_name
 
 module StringSet = Set.Make(String)
 
@@ -23,37 +23,37 @@ let remove_multiple reg names =
 let remove reg name =
   remove_multiple reg [name]
 
-let build_package reg name =
+let build_library reg name =
   match Metadata.mem reg.metadata name with
-  | false -> failwith (Printf.sprintf "Package %s is not found" name)
+  | false -> failwith (Printf.sprintf "Library %s is not found" name)
   | true ->
-    (* TODO properly build the package *)
+    (* TODO properly build the library *)
     let dir = Repository.directory reg.repository name in
-    let package = Package.read_dir dir in
-    Package.to_string package |> print_endline;
+    let library = Library.read_dir dir in
+    Library.to_string library |> print_endline;
     Store.remove reg.registry name;
-    Store.add_package reg.registry name package
+    Store.add_library reg.registry name library
 
-(* TODO build only obsoleted packages *)
+(* TODO build only obsoleted libraries *)
 let update_all reg =
-  let updated_packages = list reg in
-  List.iter ~f:(build_package reg) updated_packages;
-  Some updated_packages
+  let updated_libraries = list reg in
+  List.iter ~f:(build_library reg) updated_libraries;
+  Some updated_libraries
 
 (* Advanced operations *)
 let gc reg =
-  let current_packages = list reg |> StringSet.of_list in
-  let valid_packages = Metadata.list reg.metadata |> StringSet.of_list in
-  let broken_packages = StringSet.diff current_packages valid_packages in
-  StringSet.to_list broken_packages
+  let current_libraries = list reg |> StringSet.of_list in
+  let valid_libraries = Metadata.list reg.metadata |> StringSet.of_list in
+  let broken_libraries = StringSet.diff current_libraries valid_libraries in
+  StringSet.to_list broken_libraries
   |> remove_multiple reg
 
-let initialize packages_dir metadata_file =
-  Store.initialize packages_dir;
+let initialize libraries_dir metadata_file =
+  Store.initialize libraries_dir;
   Metadata.initialize metadata_file
 
-let read package_dir repository metadata_file = {
-    registry = Store.read package_dir;
+let read library_dir repository metadata_file = {
+    registry = Store.read library_dir;
     repository = repository;
     metadata = metadata_file;
   }
diff --git a/src/repository.ml b/src/repository.ml
index db4e446..8433542 100644
--- a/src/repository.ml
+++ b/src/repository.ml
@@ -1,7 +1,7 @@
 open Core
 
-type package_name = string
-exception RegisteredAlready of package_name
+type library_name = string
+exception RegisteredAlready of library_name
 
 module StringSet = Set.Make(String)
 
@@ -32,25 +32,25 @@ let add_dir reg name dir =
 
 let update reg name =
   match Metadata.find reg.metadata name with
-  | None -> failwith (Printf.sprintf "Package %s is not found" name)
+  | None -> failwith (Printf.sprintf "Library %s is not found" name)
   | Some metadata -> begin match Uri.scheme metadata.url with
     | Some "file" ->
       let dir = Uri.path metadata.url in
-      let package = Package.read_dir dir in
-      Package.to_string package |> print_endline;
+      let library = Library.read_dir dir in
+      Library.to_string library |> print_endline;
       Store.remove reg.cache name;
-      Store.add_package reg.cache name package
+      Store.add_library reg.cache name library
     | None ->
-      failwith (Printf.sprintf "BUG: URL scheme of package %s is unknown." name)
+      failwith (Printf.sprintf "BUG: URL scheme of library %s is unknown." name)
     | Some s ->
       failwith (Printf.sprintf "Unknown scheme %s." s)
   end
 
-(* TODO build only obsoleted packages *)
+(* TODO build only obsoleted libraries *)
 let update_all reg =
-  let updated_packages = list reg in
-  List.iter ~f:(update reg) updated_packages;
-  Some updated_packages
+  let updated_libraries = list reg in
+  List.iter ~f:(update reg) updated_libraries;
+  Some updated_libraries
 
 (* Advanced operations *)
 (* TODO Implement lock *)
@@ -68,18 +68,18 @@ let add reg name uri =
   update_all reg
 
 let gc reg =
-  let current_packages = list reg |> StringSet.of_list in
-  let valid_packages = Metadata.list reg.metadata |> StringSet.of_list in
-  let broken_packages = StringSet.diff current_packages valid_packages in
-  StringSet.to_list broken_packages
+  let current_libraries = list reg |> StringSet.of_list in
+  let valid_libraries = Metadata.list reg.metadata |> StringSet.of_list in
+  let broken_libraries = StringSet.diff current_libraries valid_libraries in
+  StringSet.to_list broken_libraries
   |> remove_multiple reg
 
-let initialize packages_dir metadata_file =
-  Store.initialize packages_dir;
+let initialize libraries_dir metadata_file =
+  Store.initialize libraries_dir;
   Metadata.initialize metadata_file
 
-let read package_dir metadata_file = {
-    cache = Store.read package_dir;
+let read library_dir metadata_file = {
+    cache = Store.read library_dir;
     metadata = metadata_file;
   }
 
diff --git a/src/version.ml b/src/satyrographosDirs.ml
similarity index 52%
rename from src/version.ml
rename to src/satyrographosDirs.ml
index 9c4fd61..d990f27 100644
--- a/src/version.ml
+++ b/src/satyrographosDirs.ml
@@ -1,27 +1,26 @@
 open Core
 
-let version_filepath d =
-  FilePath.concat d "version"
+let repository_dir sg_dir = Filename.concat sg_dir "repo"
+let library_dir sg_dir = Filename.concat sg_dir "libraries"
+let metadata_file sg_dir = Filename.concat sg_dir "metadata"
+let version_file sg_dir = FilePath.concat sg_dir "version"
 
-let packages_dirpath d =
-  FilePath.concat d "packages"
-
-let mark_version d version =
-  let file = version_filepath d in
+let mark_scheme_version d version =
+  let file = version_file d in
   let write_version ch =
     Out_channel.output_string ch (string_of_int version)
   in
   Out_channel.with_file file ~append:false ~f:write_version
 
-let get_version d =
-  let file = version_filepath d in
+let get_scheme_version d =
+  let file = version_file d in
   let read_version ch =
     let line = In_channel.input_line ch in
     Option.value_exn line
     |> int_of_string
   in
-  match FileUtil.test FileUtil.Is_file file, FileUtil.test FileUtil.Is_dir (packages_dirpath d) with
-  | true, _ -> Some (In_channel.with_file file ~f:read_version)
-  | false, true -> Some 0
+  match FileUtil.test FileUtil.Is_file file, FileUtil.test FileUtil.Is_dir (library_dir d) with
   | false, false -> None
-
+  | false, true -> Some 0
+  | true, false -> Some 0
+  | true, _ -> Some (In_channel.with_file file ~f:read_version)
diff --git a/src/satysfiRegistry.ml b/src/satysfiRegistry.ml
index 91fd28a..1b5c7a4 100644
--- a/src/satysfiRegistry.ml
+++ b/src/satysfiRegistry.ml
@@ -1,9 +1,10 @@
-type package_name = string
-
 type t = {
-  package_dir: string;
+  registy_dir: string;
 }
 
-let list reg = FileUtil.ls reg.package_dir |> List.map FilePath.basename
-let directory reg name = Filename.concat reg.package_dir name
+let read registy_dir = {
+  registy_dir
+}
+let list reg = FileUtil.ls reg.registy_dir |> List.map FilePath.basename
+let directory reg name = Filename.concat reg.registy_dir name
 let mem reg name = directory reg name |> FileUtil.test FileUtil.Is_dir
diff --git a/src/store.ml b/src/store.ml
index dc21a4c..bef6e1d 100644
--- a/src/store.ml
+++ b/src/store.ml
@@ -1,15 +1,15 @@
 open Core
 
-type package_name = string
-exception RegisteredAlready of package_name
+type library_name = string
+exception RegisteredAlready of library_name
 
 type store = {
-  package_dir: string;
+  library_dir: string;
 }
 
 (* Basic operations *)
-let list reg = FileUtil.ls reg.package_dir |> List.map ~f:FilePath.basename |> List.sort ~compare:String.compare
-let directory reg name = Filename.concat reg.package_dir name
+let list reg = FileUtil.ls reg.library_dir |> List.map ~f:FilePath.basename |> List.sort ~compare:String.compare
+let directory reg name = Filename.concat reg.library_dir name
 let mem reg name = directory reg name |> FileUtil.test FileUtil.Is_dir
 let remove_multiple reg names =
   List.map ~f:(directory reg) names |> FileUtil.rm ~force:Force ~recurse:true
@@ -23,31 +23,31 @@ let add_dir reg name dir =
   | false, true -> add_dir reg name dir
   (* | false, false -> FileUtil.cp ~recurse:true [dir] (directory reg name) *)
 
-let add_package reg name package =
+let add_library reg name library =
   if mem reg name
   then failwith (Printf.sprintf "%s is already registered. Please remove it first." name)
-  else Package.write_dir (directory reg name) package
+  else Library.write_dir (directory reg name) library
 
-let initialize packages_dir =
-  FileUtil.mkdir ~parent:true packages_dir
+let initialize libraries_dir =
+  FileUtil.mkdir ~parent:true libraries_dir
 
-let read package_dir = {
-    package_dir = package_dir;
+let read library_dir = {
+    library_dir = library_dir;
   }
 
 (* Tests *)
 open Core
 let create_new_reg dir =
-  let packages_dir = Filename.concat dir "packages" in
-  initialize packages_dir;
-  read packages_dir
+  let registry_dir = Filename.concat dir "registry" in
+  initialize registry_dir;
+  read registry_dir
 let with_new_reg f =
   let dir = Filename.temp_dir "Satyrographos" "Store" in
   protect ~f:(fun () -> create_new_reg dir |> f) ~finally:(fun () -> FileUtil.rm ~force:Force ~recurse:true [dir])
 
-let test_package_list ~expect reg =
+let test_library_list ~expect reg =
   [%test_result: string list] ~expect (list reg)
-let test_package_content ~expect reg p =
+let test_library_content ~expect reg p =
   [%test_result: string list] ~expect begin
     let target_dir = directory reg p in
     target_dir |> FileUtil.ls |> List.map ~f:(FilePath.make_relative target_dir)
@@ -58,62 +58,62 @@ let%test "store: list: empty" = with_new_reg begin fun reg ->
     list reg = []
   end
 let%test_unit "store: add empty dir" = with_new_reg begin fun reg ->
-    let dir = Filename.temp_dir "Satyrographos" "Package" in
+    let dir = Filename.temp_dir "Satyrographos" "Library" in
     add_dir reg "a" dir;
-    test_package_list ~expect:["a"] reg;
+    test_library_list ~expect:["a"] reg;
     [%test_result: bool] ~expect:true (mem reg "a");
     [%test_result: bool] ~expect:false (mem reg "b");
     [%test_result: bool] ~expect:true (directory reg "a" |> FileUtil.(test Is_dir ))
   end
 
 let%test_unit "store: add nonempty dir" = with_new_reg begin fun reg ->
-    let dir = Filename.temp_dir "Satyrographos" "Package" in
+    let dir = Filename.temp_dir "Satyrographos" "Library" in
     FilePath.concat dir "c" |> FileUtil.touch;
     add_dir reg "a" dir;
-    test_package_list ~expect:["a"] reg;
+    test_library_list ~expect:["a"] reg;
     [%test_result: bool] ~expect:true (mem reg "a");
     [%test_result: bool] ~expect:false (mem reg "b");
     [%test_result: bool] ~expect:true (directory reg "a" |> FileUtil.(test Is_dir));
-    test_package_content ~expect:["c"] reg "a"
+    test_library_content ~expect:["c"] reg "a"
   end
 
 let%test_unit "store: add nonempty dir twice" = with_new_reg begin fun reg ->
-    let dir1 = Filename.temp_dir "Satyrographos" "Package" in
+    let dir1 = Filename.temp_dir "Satyrographos" "Library" in
     FilePath.concat dir1 "c" |> FileUtil.touch;
     add_dir reg "a" dir1;
-    test_package_list ~expect:["a"] reg;
-    test_package_content ~expect:["c"] reg "a";
-    let dir2 = Filename.temp_dir "Satyrographos" "Package" in
+    test_library_list ~expect:["a"] reg;
+    test_library_content ~expect:["c"] reg "a";
+    let dir2 = Filename.temp_dir "Satyrographos" "Library" in
     FilePath.concat dir2 "d" |> FileUtil.touch;
     add_dir reg "a" dir2;
-    test_package_list ~expect:["a"] reg;
-    test_package_content ~expect:["d"] reg "a"
+    test_library_list ~expect:["a"] reg;
+    test_library_content ~expect:["d"] reg "a"
   end
 
 let%test_unit "store: added dir must be copied" = with_new_reg begin fun reg ->
-    let dir = Filename.temp_dir "Satyrographos" "Package" in
+    let dir = Filename.temp_dir "Satyrographos" "Library" in
     FilePath.concat dir "c" |> FileUtil.touch;
     add_dir reg "a" dir;
-    test_package_list ~expect:["a"] reg;
-    test_package_content ~expect:["c"] reg "a";
+    test_library_list ~expect:["a"] reg;
+    test_library_content ~expect:["c"] reg "a";
     FilePath.concat dir "d" |> FileUtil.touch;
-    test_package_list ~expect:["a"] reg;
-    test_package_content ~expect:["c"] reg "a";
+    test_library_list ~expect:["a"] reg;
+    test_library_content ~expect:["c"] reg "a";
     FileUtil.rm [FilePath.concat dir "c"];
-    test_package_list ~expect:["a"] reg;
-    test_package_content ~expect:["c"] reg "a";
+    test_library_list ~expect:["a"] reg;
+    test_library_content ~expect:["c"] reg "a";
   end
 
 let%test_unit "store: add the same directory twice with different contents" = with_new_reg begin fun reg ->
-    let dir = Filename.temp_dir "Satyrographos" "Package" in
+    let dir = Filename.temp_dir "Satyrographos" "Library" in
     FilePath.concat dir "c" |> FileUtil.touch;
     add_dir reg "a" dir;
-    test_package_list ~expect:["a"] reg;
-    test_package_content ~expect:["c"] reg "a";
+    test_library_list ~expect:["a"] reg;
+    test_library_content ~expect:["c"] reg "a";
     FilePath.concat dir "d" |> FileUtil.touch;
     FileUtil.rm [FilePath.concat dir "c"];
     add_dir reg "b" dir;
-    test_package_list ~expect:["a"; "b"] reg;
-    test_package_content ~expect:["c"] reg "a";
-    test_package_content ~expect:["d"] reg "b";
+    test_library_list ~expect:["a"; "b"] reg;
+    test_library_content ~expect:["c"] reg "a";
+    test_library_content ~expect:["d"] reg "b";
   end
diff --git a/src/systemFontPackage.ml b/src/systemFontLibrary.ml
similarity index 90%
rename from src/systemFontPackage.ml
rename to src/systemFontLibrary.ml
index 755d088..8f4f39f 100644
--- a/src/systemFontPackage.ml
+++ b/src/systemFontLibrary.ml
@@ -91,9 +91,9 @@ let font_to_json_and_hash prefix f =
         (name f, `Variant ("Collection", Some value)), (filepath f, f.file)
       )
 
-let fonts_to_package prefix fonts =
+let fonts_to_library prefix fonts =
   let add_variant = function
-    | [] -> failwith "BUG: fonts_to_package"
+    | [] -> failwith "BUG: fonts_to_library"
     | [f] -> `Single f
     | fs -> `Collection fs
   in
@@ -107,16 +107,16 @@ let fonts_to_package prefix fonts =
   in
   let hash_filename_fonts = "hash/fonts.satysfi-hash" in
   let hash_path_fonts = "#Automatically generated from the system fonts#" in
-  Package.{
-    hashes = PackageFiles.singleton hash_filename_fonts ([hash_path_fonts], `Assoc hash);
-    files = PackageFiles.of_alist_reduce files ~f:(fun f1 f2 ->
+  Library.{
+    hashes = LibraryFiles.singleton hash_filename_fonts ([hash_path_fonts], `Assoc hash);
+    files = LibraryFiles.of_alist_reduce files ~f:(fun f1 f2 ->
       begin if not (String.equal f1 f2)
         then Printf.printf "WARNING: %s and %s have conflicting filename.\n" f1 f2
       end;
       f1
     );
-    dependencies = Package.Dependency.empty;
+    dependencies = Library.Dependency.empty;
   }
 
-let get_package prefix () =
-  font_list () |> fonts_to_package prefix
+let get_library prefix () =
+  font_list () |> fonts_to_library prefix