we don't use the term clients anymore, windows is the better term

dwm.1

@@ -22,7 +22,7 @@ dwm contains a small status bar which displays all available tags, the mode,
 the title of the focused window, and the text read from standard input. The
 selected tags are indicated with a different color. The tags of the focused
 window are indicated with a filled square in the top left corner.  The tags
-which are applied to one or more clients are indicated with an empty square in
+which are applied to one or more windows are indicated with an empty square in
 the top left corner.
 .P
 dwm draws a 1-pixel border around windows to indicate the focus state.