Merge pull request #243 from wking/changeset-clarification

serialization: Remove "changeset" from terminology

serialization.md

@@ -9,12 +9,13 @@ This specification uses the following terms:
 
 <dl>
     <dt>
-        Layer
+        [Layer](layer.md)
     </dt>
     <dd>
-        Images are composed of <i>layers</i>.
-	Each layer is a set of filesystem changes.
+        Image filesystems are composed of <i>layers</i>.
+        Each layer represents a set of filesystem changes in a tar-based [layer format](layer.md), recording files to be added, changed, or deleted relative to its parent layer.
 	Layers do not have configuration metadata such as environment variables or default arguments - these are properties of the image as a whole rather than any particular layer.
+        Using a layer-based or union filesystem such as AUFS, or by computing the diff from filesystem snapshots, the filesystem changeset can be used to present a series of image layers as if they were one cohesive filesystem.
     </dd>
     <dt>
         Image JSON
@@ -25,13 +26,6 @@ This specification uses the following terms:
 	This JSON is considered to be immutable, because changing it would change the computed ImageID.
 	Changing it means creating a new derived image, instead of changing the existing image.
     </dd>
-    <dt>
-        Image Filesystem Changeset
-    </dt>
-    <dd>
-        Each layer has an archive of the files which have been added, changed, or deleted relative to its parent layer.
-	Using a layer-based or union filesystem such as AUFS, or by computing the diff from filesystem snapshots, the filesystem changeset can be used to present a series of image layers as if they were one cohesive filesystem.
-    </dd>
     <dt>
         Layer DiffID
     </dt>