term: review usage of "experiment" (and remove "variant")

mainly for get-started issues per #599

static/docs/command-reference/import-url.md

@@ -203,9 +203,9 @@ Let's use the [Get Started](/doc/get-started) project again, simulating an
 updated external data source. (Remember to prepare the <abbr>workspace</abbr>,
 as explained in [Examples](#examples))
 
-To make it easy to experiment with this, let's use a local machine directory
-(external to the workspace) to simulate a remote data source location. (In real
-life, the data file will probably be on a remote server.) Run these commands:
+To illustrate this scenario, let's use a local machine directory (external to
+the workspace) to simulate a remote data source location. (In real life, the
+data file will probably be on a remote server.) Run these commands:
 
 ```dvc
 $ mkdir /tmp/dvc-import-url-example

static/docs/command-reference/metrics/index.md

@@ -26,7 +26,7 @@ containing metrics to track. (See `--metrics` option of `dvc run`.) Metrics are
 project-specific numeric values e.g. `AUC`, `ROC`, etc. DVC itself does not
 ascribe any specific meaning for these numbers. Usually these numbers are
 produced by the model evaluation script and serve as a way to compare and pick
-the best performing experiment variant.
+the best performing experiment.
 
 [Add](/doc/command-reference/metrics/add),
 [show](/doc/command-reference/metrics/show),

static/docs/command-reference/metrics/show.md

@@ -83,7 +83,7 @@ extension.)
   results or parse files that are not in a corresponding format in this case.
 
 - `-a`, `--all-branches` - get and print metric file contents across all Git
-  branches. It can be used to compare different variants of an experiment.
+  branches. It can be used to compare different experiments.
 
 - `-T`, `--all-tags` - get and print metric file contents across all Git tags.
   Similar to `-a` above. Note that both options can be combined, for example

static/docs/command-reference/pull.md

@@ -66,7 +66,7 @@ reflinks or hardlinks to put it in the workspace without copying. See
 
 - `-a`, `--all-branches` - determines the files to download by examining
   DVC-files in all Git branches of the project repository (if using Git). It's
-  useful if branches are used to track checkpoints of an experiment or project.
+  useful if branches are used to track experiments or project checkpoints.
 
 - `-T`, `--all-tags` - the same as `-a`, `--all-branches` but Git tags are used
   to save different experiments or project checkpoints. Note that both options

static/docs/command-reference/push.md

@@ -75,7 +75,7 @@ to push.
 
 - `-a`, `--all-branches` - determines the files to upload by examining DVC-files
   in all Git branches of the project repository (if using Git). It's useful if
-  branches are used to track checkpoints of an experiment or project.
+  branches are used to track experiments or project checkpoints.
 
 - `-T`, `--all-tags` - the same as `-a`, `--all-branches`, but Git tags are used
   to save different experiments or project checkpoints. Note that both options