Emily Dickinson Lexicon

COM'PLE-MENT, n. [L. complementum, from compleo, to fill; con and pleo, to fill. Literally, a filling.]

1. Fullness; completion; whence, perfection. They, as they feasted, had their fill, / For a full complement of all their ill. – Hub. Tales.
2. Full quantity or number; the quantity or number limited; as, a company has its complement of men; a ship has its complement of stores.
3. That which is added, not as necessary, but as ornamental; something adventitious to the main thing; ceremony. [See Compliment.] Garnished and decked in modest complement. – Shak.
4. In geometry, what remains of the quadrant of a circle, or of ninety degrees, after any arch has been taken from it. Thus, if the arch taken is thirty degrees, its complement is sixty. – Bailey. Johnson.
5. In astronomy, the distance of a star from the zenith. – Johnson.
6. Arithmetical complement of a logarithm, is what the logarithm wants of 10,000,000. Chambers.
7. In fortification, the complement of the curtain is that part in the interior side which makes the demigorge.