Webster’s Revised Unabridged Dictionary · 1913
Complemental
Com′ple·men′tal (kŏm′plē·mĕn′tal), a. 1. Supplying, or tending to supply, a deficiency; fully completing. "Complemental ceremony." Prynne.
2. Complimentary; courteous. [Obs.] Shak.
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 (Zoöl.), peculiar small males living parasitically on the ordinary hermaphrodite individuals of certain barnacles.