Com″ple‐ment (?), n. [L. complementun: cf. F. complément. See Complete, v. t., and cf. Compliment.] 1. That which fills up or completes; the quantity or number required to fill a thing or make it complete.
2. That which is required to supply a deficiency, or to complete a symmetrical whole.
History is the complement of poetry.
Sir J. Stephen.
3. Full quantity, number, or amount; a complete set; completeness.
To exceed his complement and number appointed him which was one hundred and twenty persons.
Hakluyt.
4. (Math.) A second quantity added to a given quantity to make it equal to a third given quantity.
5. Something added for ornamentation; an accessory.
Without vain art or curious complements.
Spenser.
6. (Naut.) The whole working force of a vessel.
7. (Mus.) The interval wanting to complete the octave; — the fourth is the complement of the fifth, the sixth of the third.
8. A compliment. Shak.
Arithmetical compliment of a logarithm. See under Logarithm. — Arithmetical complement of a number(Math.), the difference between that number and the next higher power of 10; as, 4 is the complement of 6, and 16 of 84. — Complement of anarc or angle(Geom.), the difference between that arc or angle and 90°. — Complement of a parallelogram. (Math.) See Gnomon. — In her complement(Her.), said of the moon when represented as full.