diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
index be88c7c9e8..3ff41ed81b 100644
--- a/activerecord/lib/active_record/aggregations.rb
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -33,7 +33,7 @@ def init_internals # :nodoc:
     # the database).
     #
     #   class Customer < ActiveRecord::Base
-    #     composed_of :balance, class_name: "Money", mapping: %w(balance amount)
+    #     composed_of :balance, class_name: "Money", mapping: %w(amount currency)
     #     composed_of :address, mapping: [ %w(address_street street), %w(address_city city) ]
     #   end
     #