diff --git a/src/os_unix.h b/src/os_unix.h
index 821462c..d99d1c8 100644
--- a/src/os_unix.h
+++ b/src/os_unix.h
@@ -483,7 +483,7 @@
 # endif
 # ifndef VMS
 #  ifdef __MVS__
-  /* on OS390 Unix getenv() doesn't return a pointer to persistant
+  /* on OS390 Unix getenv() doesn't return a pointer to persistent
    * storage -> use __getenv() */
 #   define mch_getenv(x) (char_u *)__getenv((char *)(x))
 #  else