diff --git a/actionpack/lib/action_dispatch/testing/assertions/selector.rb b/actionpack/lib/action_dispatch/testing/assertions/selector.rb
index fe149c654d57a87dafac6ea9f28c2092a52f480a..8eed85bce2525a6eef989bed00fdb0ca5c8633b9 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/selector.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/selector.rb
@@ -340,7 +340,7 @@ def count_description(min, max, count) #:nodoc:
       # element +encoded+. It then calls the block with all un-encoded elements.
       #
       # ==== Examples
-      #   # Selects all bold tags from within the title of an ATOM feed's entries (perhaps to nab a section name prefix)
+      #   # Selects all bold tags from within the title of an Atom feed's entries (perhaps to nab a section name prefix)
       #   assert_select "feed[xmlns='http://www.w3.org/2005/Atom']" do
       #     # Select each entry item and then the title item
       #     assert_select "entry>title" do
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helper.rb b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
index 40a950c644809c4532a63bd8a8f975797fc35773..ab8a56e81375644eef85c8cce018ed2d30b7ad1e 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
@@ -198,7 +198,7 @@ module AssetTagHelper
       include JavascriptTagHelpers
       include StylesheetTagHelpers
       # Returns a link tag that browsers and news readers can use to auto-detect
-      # an RSS or ATOM feed. The +type+ can either be <tt>:rss</tt> (default) or
+      # an RSS or Atom feed. The +type+ can either be <tt>:rss</tt> (default) or
       # <tt>:atom</tt>. Control the link options in url_for format using the
       # +url_options+. You can modify the LINK tag itself in +tag_options+.
       #
diff --git a/railties/guides/source/action_view_overview.textile b/railties/guides/source/action_view_overview.textile
index e2b69fa0d5eff16cd639428ced4cea70d9ac32ac..bb1b3b5fd84cf03b159049c80fa636691258a50d 100644
--- a/railties/guides/source/action_view_overview.textile
+++ b/railties/guides/source/action_view_overview.textile
@@ -570,7 +570,7 @@ stylesheet_link_tag :monkey # =>
 
 h5. auto_discovery_link_tag
 
-Returns a link tag that browsers and news readers can use to auto-detect an RSS or ATOM feed.
+Returns a link tag that browsers and news readers can use to auto-detect an RSS or Atom feed.
 
 <ruby>
 auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", {:title => "RSS Feed"}) # =>
@@ -663,7 +663,7 @@ h4. AtomFeedHelper
 
 h5. atom_feed
 
-This helper makes building an ATOM feed easy. Here's a full usage example:
+This helper makes building an Atom feed easy. Here's a full usage example:
 
 *config/routes.rb*
 
diff --git a/railties/guides/source/layouts_and_rendering.textile b/railties/guides/source/layouts_and_rendering.textile
index 5cff2d0893cc6575524c76a25e1a620debd5ba46..c3df9d203f47983924f912a64272a7dd13ace70a 100644
--- a/railties/guides/source/layouts_and_rendering.textile
+++ b/railties/guides/source/layouts_and_rendering.textile
@@ -656,7 +656,7 @@ WARNING: The asset tag helpers do _not_ verify the existence of the assets at th
 
 h5. Linking to Feeds with the +auto_discovery_link_tag+
 
-The +auto_discovery_link_tag+ helper builds HTML that most browsers and newsreaders can use to detect the presences of RSS or ATOM feeds. It takes the type of the link (+:rss+ or +:atom+), a hash of options that are passed through to url_for, and a hash of options for the tag:
+The +auto_discovery_link_tag+ helper builds HTML that most browsers and newsreaders can use to detect the presences of RSS or Atom feeds. It takes the type of the link (+:rss+ or +:atom+), a hash of options that are passed through to url_for, and a hash of options for the tag:
 
 <erb>
 <%= auto_discovery_link_tag(:rss, {:action => "feed"},