diff --git a/doc/guides/symbol.md b/doc/guides/symbol.md
index dcdb58459..913cb495c 100644
--- a/doc/guides/symbol.md
+++ b/doc/guides/symbol.md
@@ -71,7 +71,7 @@ header.
 For `MRB_OPSYM()`, specify the names corresponding to operators (see
 `MRuby::Presym::OPERATORS` in `lib/mruby/presym.rb` for the names that
 can be specified for it). Other than that, describe only word characters
-excluding leading and ending punctuations.
+excluding leading and ending punctuation.
 
 These macros are converted to static symbol IDs at compile time, unless
 preallocate symbols are disabled by `conf.disable_presym`. In that case,
diff --git a/include/mruby/presym.h b/include/mruby/presym.h
index 7c6374ad1..cb6922218 100644
--- a/include/mruby/presym.h
+++ b/include/mruby/presym.h
@@ -30,7 +30,7 @@
  * For `MRB_OPSYM`, specify the names corresponding to operators (see
  * `MRuby::Presym::OPERATORS` in `lib/mruby/presym.rb` for the names that
  * can be specified for it). Other than that, describe only word characters
- * excluding leading and ending punctuations.
+ * excluding leading and ending punctuation.
  *
  * These macros are expanded to `mrb_intern_lit` if presym is disabled,
  * therefore the mruby state variable is required. The above macros can be