diff --git a/src/tools/common.jam b/src/tools/common.jam
index fd6650c3d..4946a33bf 100644
--- a/src/tools/common.jam
+++ b/src/tools/common.jam
@@ -567,7 +567,7 @@ rule file-touch-command ( )
 
 rule MkDir
 {
-    # If dir exists, don't update it. Do this even for $(DOT).
+    # If dir exists, do not update it. Do this even for $(DOT).
     NOUPDATE $(<) ;
 
     if $(<) != $(DOT) && ! $($(<)-mkdir)