DOCS-734 migrate natural order wiki

source/reference/glossary.txt

@@ -463,11 +463,17 @@ Glossary
       management.
 
    natural order
-      The order in which a database stores documents on disk.
-      Typically this order is the same as the
-      insertion order. :term:`Capped collections <capped collection>`,
-      among other things, guarantee that insertion order and natural
-      order are identical.
+      The order in which a database stores documents on disk. Typically
+      this order is the same as the insertion order, though it is not
+      guaranteed to be. :term:`Capped collections <capped collection>`
+      guarantee that insertion order and natural order are identical.
+
+      When you execute :method:`find() <db.collection.find()>` with no
+      parameters, the database returns documents in forward natural
+      order. When you execute :method:`find() <db.collection.find()>`
+      and include :method:`sort() <cursor.sort()>` with a parameter of
+      ``$natural:-1``, the database returns documents in reverse natural
+      order.
 
    primary key
       A record's unique, immutable identifier. In an :term:`RDBMS`, the primary

source/reference/method/cursor.sort.txt

@@ -47,3 +47,13 @@ cursor.sort()
       than 32 megabytes, MongoDB will return an error. Use
       :method:`cursor.limit()`, or create an index on the field that you're
       sorting to avoid this error.
+
+.. todo:: add an explanation of the $natural parameter:
+
+          The $natural parameter returns items according to their order
+          on disk. (link to glossary item on natural order)
+
+          For example, to return items in reverse order on disk, you
+          would invoke:
+
+          db.collection.find().sort({$natural:-1})