Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
supplement, complement (nn., vv.)
When you supplement something, you “add to it”: We’ll supplement our rations with what we can scrounge. When you complement something, you “complete it, fill it out”: His powerful ground game complemented her excellent volleying and net play. A supplement is “something added”: The new book was a supplement to the old. A complement is “something that fills out or completes,” as in Her recent essay complements the contributions of her predecessors; The arrival of the new recruits gave us a full complement of troops. See also COMPLEMENT.
