diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index ff601fb9cf2eba50092f7f50b5ef4ee69be1e295..43529e3e96c6ff932573107fbdd9ce49613d3be5 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -2198,7 +2198,7 @@ This method accepts three options:
 * `:words_connector`: What is used to join the elements of arrays with 3 or more elements, except for the last two. Default is ", ".
 * `:last_word_connector`: What is used to join the last items of an array with 3 or more elements. Default is ", and ".
 
-The defaults for these options can be localised, their keys are:
+The defaults for these options can be localized, their keys are:
 
 | Option                 | I18n key                            |
 | ---------------------- | ----------------------------------- |