- Complement of an angle
- Complement Com"ple*ment, n. [L. complementun: cf. F.
compl['e]ment. 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.
[1913 Webster]
2. That which is required to supply a deficiency, or to complete a symmetrical whole. [1913 Webster]

History is the complement of poetry. --Sir J. Stephen. [1913 Webster]

3. Full quantity, number, or amount; a complete set; completeness. [1913 Webster]

To exceed his complement and number appointed him which was one hundred and twenty persons. --Hakluyt. [1913 Webster]

4. (Math.) A second quantity added to a given quantity to make it equal to a third given quantity. [1913 Webster]

5. Something added for ornamentation; an accessory. [Obs.] [1913 Webster]

Without vain art or curious complements. --Spenser. [1913 Webster]

6. (Naut.) The whole working force of a vessel. [1913 Webster]

7. (Mus.) The interval wanting to complete the octave; -- the fourth is the complement of the fifth, the sixth of the third. [1913 Webster]

8. A compliment. [Obs.] --Shak. [1913 Webster]

{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 an arc} or {Complement of an angle} (Geom.), the difference between that arc or angle and 90[deg].

{Complement of a parallelogram}. (Math.) See {Gnomon}.

{In her complement} (Her.), said of the moon when represented as full. [1913 Webster]

*The Collaborative International Dictionary of English.
2000.*