diff --git a/activerecord/test/cases/nested_attributes_test.rb b/activerecord/test/cases/nested_attributes_test.rb
index 2ae9cb4888..532d4654b5 100644
--- a/activerecord/test/cases/nested_attributes_test.rb
+++ b/activerecord/test/cases/nested_attributes_test.rb
@@ -937,13 +937,13 @@ class TestHasManyAutosaveAssociationWhichItselfHasAutosaveAssociations < ActiveR
     @trinket = @part.trinkets.create!(:name => "Necklace")
   end
 
-  test "if association is not loaded and association record is saved and then in memory record attributes should be saved" do
+  test "if association is not loaded and association record is saved and then in-memory record attributes should be saved" do
     @ship.parts_attributes=[{:id => @part.id,:name =>'Deck'}]
     assert_equal 1, @ship.association(:parts).target.size
     assert_equal 'Deck', @ship.parts[0].name
   end
 
-  test "if association is not loaded and child doesn't change and I am saving a grandchild then in memory record should be used" do
+  test "if association is not loaded and child doesn't change and I am saving a grandchild then in-memory record should be used" do
     @ship.parts_attributes=[{:id => @part.id,:trinkets_attributes =>[{:id => @trinket.id, :name => 'Ruby'}]}]
     assert_equal 1, @ship.association(:parts).target.size
     assert_equal 'Mast', @ship.parts[0].name
diff --git a/activerecord/test/cases/relation_scoping_test.rb b/activerecord/test/cases/relation_scoping_test.rb
index 1e2093273e..ec1a6eda0c 100644
--- a/activerecord/test/cases/relation_scoping_test.rb
+++ b/activerecord/test/cases/relation_scoping_test.rb
@@ -527,7 +527,7 @@ class DefaultScopingTest < ActiveRecord::TestCase
 
   def test_default_scope_is_threadsafe
     if in_memory_db?
-      skip "in memory db can't share a db between threads"
+      skip "in-memory db can't share a db between threads"
     end
 
     threads = []
diff --git a/activesupport/lib/active_support/cache/file_store.rb b/activesupport/lib/active_support/cache/file_store.rb
index 85e7e21624..9460532af0 100644
--- a/activesupport/lib/active_support/cache/file_store.rb
+++ b/activesupport/lib/active_support/cache/file_store.rb
@@ -8,7 +8,7 @@ module ActiveSupport
     # A cache store implementation which stores everything on the filesystem.
     #
     # FileStore implements the Strategy::LocalCache strategy which implements
-    # an in memory cache inside of a block.
+    # an in-memory cache inside of a block.
     class FileStore < Store
       attr_reader :cache_path
 
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
index e07294178b..5234cdb4ce 100644
--- a/activesupport/lib/active_support/cache/mem_cache_store.rb
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -21,7 +21,7 @@ module ActiveSupport
     #   server goes down, then MemCacheStore will ignore it until it comes back up.
     #
     # MemCacheStore implements the Strategy::LocalCache strategy which implements
-    # an in memory cache inside of a block.
+    # an in-memory cache inside of a block.
     class MemCacheStore < Store
       module Response # :nodoc:
         STORED      = "STORED\r\n"
diff --git a/activesupport/lib/active_support/cache/strategy/local_cache.rb b/activesupport/lib/active_support/cache/strategy/local_cache.rb
index 0649a058aa..db5f228a70 100644
--- a/activesupport/lib/active_support/cache/strategy/local_cache.rb
+++ b/activesupport/lib/active_support/cache/strategy/local_cache.rb
@@ -4,9 +4,9 @@ require 'active_support/core_ext/string/inflections'
 module ActiveSupport
   module Cache
     module Strategy
-      # Caches that implement LocalCache will be backed by an in memory cache for the
+      # Caches that implement LocalCache will be backed by an in-memory cache for the
       # duration of a block. Repeated calls to the cache for the same key will hit the
-      # in memory cache for faster access.
+      # in-memory cache for faster access.
       module LocalCache
         # Simple memory backed cache. This cache is not thread safe and is intended only
         # for serving as a temporary memory cache for a single thread.