diff --git a/lib/puppet/parser/functions/defined.rb b/lib/puppet/parser/functions/defined.rb
index c3efc5f76..deb57a616 100644
--- a/lib/puppet/parser/functions/defined.rb
+++ b/lib/puppet/parser/functions/defined.rb
@@ -1,62 +1,67 @@
 # Test whether a given class or definition is defined
 Puppet::Parser::Functions::newfunction(:defined, :type => :rvalue, :doc => "Determine whether
-  a given type, class, resource, or node is defined, and return
-  true or false. Accepts class names, type names, resource references, and node
-  references.
-  
+  a given type or class is defined. This function can also determine whether a
+  specific resource has been declared. Returns true or false. Accepts class names,
+  type names, resource references, and node references.
+
   The `defined` function checks both native and defined types, including types
-  provided as plugins via modules. Types are checked using their names:
-  
+  provided as plugins via modules. Types and classes are both checked using their names:
+
       defined(\"file\")
       defined(\"customtype\")
-  
-  Classes are also checked using their names:
-  
       defined(\"foo\")
       defined(\"foo::bar\")
-  
-  Unlike classes and types, resource definitions are checked using resource
-  references, e.g. `defined( File['/tmp/myfile'] )`. Checking whether a given
-  resource defined is, unfortunately, dependent on the parse order of the
-  configuration, and the following code will not work:
-  
+
+  Resource declarations are checked using resource references, e.g.
+  `defined( File['/tmp/myfile'] )`. Checking whether a given resource
+  has been declared is, unfortunately, dependent on the parse order of
+  the configuration, and the following code will not work:
+
       if defined(File['/tmp/foo']) {
           notify(\"This configuration includes the /tmp/foo file.\")
       }
       file {\"/tmp/foo\":
           ensure => present,
       }
-  
+
   However, this order requirement refers to parse order only, and ordering of
-  resources in the configuration graph (e.g. with `begin` or `require`) does not
+  resources in the configuration graph (e.g. with `before` or `require`) does not
   affect the behavior of `defined`.
-  
-  You can also use `defined` to check whether a node is defined using syntax
+
+  You can also use `defined` to check whether a node is declared using syntax
   resembling a resource reference, like `Node[\"testnode.domain.com\"]`. This usage
   is not necessarily recommended, and is included here only in the spirit of
-  completeness. Checking for node definitions behaves differently from the other
-  uses of `defined`: it will only return true if a definition for the specified
-  node (the name of which must match exactly) exists in the manifest **AND** the
-  specified node matches the node whose configuration is being compiled (either
-  directly or through node inheritance). The `define` function cannot be used to
-  introspect information returned by an external node classifier. ") do |vals|
+  completeness. Note that:
+
+  * Only the node whose configuration is being compiled is considered declared;
+  the `define` function will not return information about definitions not currently
+  being used.
+  * Node definitions inherited by the current node are considered declared;
+  however, the default node is never considered declared.
+  * A node is not considered declared simply by virtue of receiving a
+  configuration; it must have matched a node definition in the manifest.
+  * The name used in the node reference must match the name used in the node
+  definition, even if this is not the node's actual certname.
+  * Regular expression node definitions cannot be checked for declaration using
+  `define`, nor can `define` be used to introspect information returned by an
+  external node classifier.") do |vals|
     result = false
     vals = [vals] unless vals.is_a?(Array)
     vals.each do |val|
       case val
       when String
         if Puppet::Type.type(val) or find_definition(val) or find_hostclass(val)
           result = true
           break
         end
       when Puppet::Resource
         if findresource(val.to_s)
           result = true
           break
         end
       else
         raise ArgumentError, "Invalid argument of type '#{val.class}' to 'defined'"
       end
     end
     result
 end