diff --git a/docs/reference/gobject/tut_gobject.xml b/docs/reference/gobject/tut_gobject.xml
index 7a2ecc77e..7754fec1e 100644
--- a/docs/reference/gobject/tut_gobject.xml
+++ b/docs/reference/gobject/tut_gobject.xml
@@ -294,7 +294,7 @@ ViewerFile *file = g_object_new (VIEWER_TYPE_FILE, NULL);
         memory will be freed or returned to the object pool for this type.
         Once the object has been freed, if it was the last instance of the type, the type's class
         will be destroyed as described in <xref linkend="gtype-instantiatable-classed"/> and
-          <xref linkend="gtype-non-instantiatable-classed"/>.
+          <xref linkend="gtype-non-instantiatable-non-classed"/>.
       </para>
 
       <para>
diff --git a/docs/reference/gobject/tut_gtype.xml b/docs/reference/gobject/tut_gtype.xml
index ee042889d..c2d51b9a5 100644
--- a/docs/reference/gobject/tut_gtype.xml
+++ b/docs/reference/gobject/tut_gtype.xml
@@ -599,7 +599,7 @@ B *b;
                   <row>
                     <!--entry>First call to <function><link linkend="g-type-create-instance">g_type_create_instance</link></function> for target type</entry-->
                     <entry>interface initialization, see 
-                      <xref linkend="gtype-non-instantiatable-classed-init"/></entry>
+                      <xref linkend="gtype-non-instantiatable-non-classed-init"/></entry>
                     <entry></entry>
                   </row>
                   <row>
@@ -610,7 +610,7 @@ B *b;
                   <row>
                     <entry morerows="2">Last call to <function><link linkend="g-type-free-instance">g_type_free_instance</link></function> for target type</entry>
                     <entry>interface destruction, see
-                      <xref linkend="gtype-non-instantiatable-classed-dest"/></entry>
+                      <xref linkend="gtype-non-instantiatable-non-classed-dest"/></entry>
                     <entry></entry>
                   </row>
                   <row>
@@ -633,8 +633,8 @@ B *b;
 
       </sect1>
 
-      <sect1 id="gtype-non-instantiatable-classed">
-        <title>Non-instantiatable classed types: interfaces</title>
+      <sect1 id="gtype-non-instantiatable-non-classed">
+        <title>Non-instantiatable non-classed types: interfaces</title>
 
         <para>
           This section covers the theory behind interfaces. See
@@ -649,7 +649,7 @@ B *b;
           be seen as a playback interface. Once you know what they do, you can
           control your CD player, MP3 player or anything that uses these symbols.
           To declare an interface you have to register a non-instantiatable
-          classed type which derives from 
+          non-classed type which derives from
           <link linkend="GTypeInterface"><type>GTypeInterface</type></link>. The following piece of code declares such an interface.
 <informalexample><programlisting>
 #define VIEWER_TYPE_EDITABLE viewer_editable_get_type ()
@@ -792,7 +792,7 @@ struct _GInterfaceInfo
 </programlisting></informalexample>
         </para>
 
-        <sect2 id="gtype-non-instantiatable-classed-init">
+        <sect2 id="gtype-non-instantiatable-non-classed-init">
           <title>Interface Initialization</title>
 
           <para>
@@ -937,7 +937,7 @@ viewer_editable_default_init (ViewerEditableInterface *iface)
         
         </sect2>
         
-        <sect2 id="gtype-non-instantiatable-classed-dest">
+        <sect2 id="gtype-non-instantiatable-non-classed-dest">
           <title>Interface Destruction</title>
 
           <para>
@@ -955,7 +955,7 @@ viewer_editable_default_init (ViewerEditableInterface *iface)
 
           <para>
             Again, it is important to understand, as in 
-            <xref linkend="gtype-non-instantiatable-classed-init"/>,
+            <xref linkend="gtype-non-instantiatable-non-classed-init"/>,
               that both <function>interface_finalize</function> and <function>base_finalize</function>
               are invoked exactly once for the destruction of each implementation of an interface. Thus,
               if you were to use one of these functions, you would need to use a static integer variable
diff --git a/docs/reference/gobject/tut_howto.xml b/docs/reference/gobject/tut_howto.xml
index 4ed178cec..9bff49b56 100644
--- a/docs/reference/gobject/tut_howto.xml
+++ b/docs/reference/gobject/tut_howto.xml
@@ -854,7 +854,7 @@ b_method_to_call (B *obj, gint some_param)
   
   <para>
     The theory behind how GObject interfaces work is given in
-    <xref linkend="gtype-non-instantiatable-classed"/>; this section covers how to
+    <xref linkend="gtype-non-instantiatable-non-classed"/>; this section covers how to
     define and implement an interface.
   </para>
 
diff --git a/gobject/gtype.h b/gobject/gtype.h
index a555a90dd..b68af22ca 100644
--- a/gobject/gtype.h
+++ b/gobject/gtype.h
@@ -304,6 +304,15 @@ G_BEGIN_DECLS
  * 
  * Checks if @type is a classed type.
  *
+ * A classed type has an associated #GTypeClass which can be derived to store
+ * class-wide virtual function pointers and data for all instances of the type.
+ * This allows for subclassing. All #GObjects are classed; none of the scalar
+ * fundamental types built into GLib are classed.
+ *
+ * Interfaces are not classed: while their #GTypeInterface struct could be
+ * considered similar to #GTypeClass, and classes can derive interfaces,
+ * #GTypeInterface doesn’t allow for subclassing.
+ *
  * Returns: %TRUE if @type is classed
  */
 #define G_TYPE_IS_CLASSED(type)                 (g_type_test_flags ((type), G_TYPE_FLAG_CLASSED))