Add term Client Platform

index.bs

@@ -475,8 +475,12 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "S
 : <dfn>Client</dfn>
 :: See [=[WAC]=], [=Conforming User Agent=].
 
+: <dfn>Client Platform</dfn>
+:: A [=client device=] and a [=client=] together make up a [=client platform=]. A single hardware device MAY be part of multiple
+    distinct [=client platforms=] at different times by running different operating systems and/or [=clients=].
+
 : <dfn>Client-Side</dfn>
-:: This refers in general to the combination of the user's [=client device=], user agent, [=authenticators=], and everything gluing
+:: This refers in general to the combination of the user's [=client platform=], [=authenticators=], and everything gluing
     it all together.
 
 : <dfn>Resident Credential</dfn>
@@ -491,7 +495,7 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "S
     [=client device=], but the [=client device=] is not expected to offload the key storage to remote entities (e.g., [=[WRP]=] Server).
 
 : <dfn>Conforming User Agent</dfn>
-:: A user agent implementing, in conjunction with the underlying platform, the [=Web Authentication API=] and algorithms
+:: A user agent implementing, in co-operation with the underlying [=client device=], the [=Web Authentication API=] and algorithms
     given in this specification, and handling communication between [=authenticators=] and [=[RPS]=].
 
 : <dfn>Credential ID</dfn>
@@ -667,12 +671,13 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "S
 
 : <dfn>Client Device</dfn>
 : <dfn>[WAC] Device</dfn>
-:: The hardware device on which the [=[WAC]=] runs, for example a smartphone, a laptop computer or a desktop computer. Also
-    referred to herein as the "platform" or "client platform".
+:: The hardware device on which the [=[WAC]=] runs, for example a smartphone, a laptop computer or a desktop computer, and the
+    operating system running on that hardware.
 
-    The distinction between this and the [=client=] is that multiple [=clients=], i.e., browser implementations, may run on the
-    same [=client device=] and have access to the same [=authenticators=] available on that [=client device=]; and that [=platform
-    authenticators=] are bound to a [=[WAC] Device=] rather than a [=[WAC]=].
+    The distinction between this and the [=client=] is that one [=client device=] MAY support running multiple [=clients=], i.e., browser
+    implementations, which all have access to the same [=authenticators=] available on that [=client device=]; and that [=platform
+    authenticators=] are bound to a [=[WAC] Device=] rather than a [=[WAC]=]. A [=client device=] and a [=client=] together make
+    up a [=client platform=].
 
 : <dfn>[WRP]</dfn>
 :: The entity whose web application utilizes the [=Web Authentication API=] to register and authenticate users. See