diff --git a/Headers/Foundation/NSGeometry.h b/Headers/Foundation/NSGeometry.h
index 7173c91..adb9786 100644
--- a/Headers/Foundation/NSGeometry.h
+++ b/Headers/Foundation/NSGeometry.h
@@ -285,7 +285,7 @@ NSHeight(NSRect aRect)
 GS_GEOM_SCOPE BOOL
 NSIsEmptyRect(NSRect aRect) GS_GEOM_ATTR;
 
-/** Returns 'YES' iff the area of aRect is zero (i.e., iff either
+/** Returns 'YES' if the area of aRect is zero (i.e., if either
  * of aRect's width or height is negative or zero). */
 GS_GEOM_SCOPE BOOL
 NSIsEmptyRect(NSRect aRect)