diff --git a/ChangeLog b/ChangeLog
index f5c5b81e65..0701a866d4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,7 @@
 Wed May 15 00:42:54 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* signal.c: need to include unistd.h for write(2).
-	  unistd.h is now included via ruby/defines.h, but should implicitly
+	  unistd.h is now included via ruby/defines.h, but should explicitly
 	  include here.  (suggested by kosaki)
 
 Tue May 14 23:43:05 2013  Tanaka Akira  <akr@fsij.org>