diff --git a/koans/about_methods.rb b/koans/about_methods.rb
index ecf7240..cbebd30 100644
--- a/koans/about_methods.rb
+++ b/koans/about_methods.rb
@@ -10,14 +10,14 @@ class AboutMethods < EdgeCase::Koan
     assert_equal __, my_global_method(2,3)
   end
 
-  def test_calling_global_methods_without_parenthesis
+  def test_calling_global_methods_without_parentheses
     result = my_global_method 2, 3
     assert_equal __, result
   end
 
   # (NOTE: We are Using eval below because the example code is
   # considered to be syntactically invalid).
-  def test_sometimes_missing_parenthesis_are_ambiguous
+  def test_sometimes_missing_parentheses_are_ambiguous
     eval "assert_equal 5, my_global_method 2, 3" # ENABLE CHECK
     #
     # Ruby doesn't know if you mean:
diff --git a/src/about_methods.rb b/src/about_methods.rb
index a31d373..3b6ad57 100644
--- a/src/about_methods.rb
+++ b/src/about_methods.rb
@@ -10,14 +10,14 @@ class AboutMethods < EdgeCase::Koan
     assert_equal __(5), my_global_method(2,3)
   end
 
-  def test_calling_global_methods_without_parenthesis
+  def test_calling_global_methods_without_parentheses
     result = my_global_method 2, 3
     assert_equal __(5), result
   end
 
   # (NOTE: We are Using eval below because the example code is
   # considered to be syntactically invalid).
-  def test_sometimes_missing_parenthesis_are_ambiguous
+  def test_sometimes_missing_parentheses_are_ambiguous
     #--
     eval "assert_equal 5, my_global_method(2, 3)" # REMOVE CHECK
     if false