diff --git doc/wm.n doc/wm.n
index a137d061b..f7f969e84 100644
--- doc/wm.n
+++ doc/wm.n
@@ -828,7 +828,7 @@ toplevel .fixed
 \fBwm resizable\fR .fixed 0 0
 .CE
 .PP
-A simple dialog-like window, centred on the screen:
+A simple dialog-like window, centered on the screen:
 .CS
 # Create and arrange the dialog contents.
 toplevel .msg
@@ -837,7 +837,7 @@ button .msg.ok \-text OK \-default active \-command {destroy .msg}
 pack .msg.ok \-side bottom \-fill x
 pack .msg.l  \-expand 1    \-fill both
 
-# Now set the widget up as a centred dialog.
+# Now set the widget up as a centered dialog.
 
 # But first, we need the geometry managers to finish setting
 # up the interior of the dialog, for which we need to run the
