Complemental

a.	1.	Supplying, or tending to supply, a deficiency; fully completing.
	2.	Complimentary; courteous. Complemental air (Physiol.) the air (averaging 100 cubic inches) which can be drawn into the lungs in addition to the tidal air, by the deepest possible inspiration. Complemental males (Zool.) peculiar small males living parasitically on the ordinary hermaphrodite individuals of certain barnacles.

Adj.

1.

complemental - acting as or providing a complement (something that completes the whole) Synonyms: complementary, completing

complementary, completing, inessential, unessential