—n.
1 a something that completes. b one of a pair, or one of two things that go together.
2 (often full complement) the full number needed to man a ship, fill a conveyance, etc.
3 Gram. a word or phrase added to a verb to complete the predicate of a sentence.
4 Biochem. a group of proteins in the blood capable of lysing bacteria etc.
5 Math. any element not belonging to a specified set or class.
6 Geom. the amount by which an angle is less than 90° (cf. SUPPLEMENT).
—v.tr.
1 complete.
2 form a complement to (the scarf complements her dress).
Derivatives:
complemental adj.
Etymology: ME f. L complementum (as COMPLETE)
Useful english dictionary. 2012.