complement

complement · noun, verb¹

1. Latin · derived fromcomplēmentum“that which fills up or completes”
2. Middle English · inherited fromcomplement
3. English todaycomplement

From Middle English complement, from Latin complēmentum (“that which fills up or completes”), from compleō (“to fill up; to complete”) (English complete). Doublet of compliment. The verb is from the noun.

complement · noun, verb²

See compliment.

Words from the same roots

First known use, by meaning

• from 16th c. The totality, the full amount or number which completes something.
• from 18th c. An angle which, together with a given angle, makes a right angle.
• from 19th c. Something which completes, something which combines with something else to make up a complete whole; loosely, something perceived to be a harmonious or desirable partner or addition.
• from 19th c. A word or group of words that completes a grammatical construction in the predicate and that describes or is identified with the subject or object.
• from 19th c. An interval which, together with the given interval, makes an octave.
• from 19th c. The color which, when mixed with the given color, gives black (for mixing pigments) or white (for mixing light).
• from 20th c. Given two sets, the set containing one set's elements that are not members of the other set (whether a relative complement or an absolute complement).
• from 20th c. One of several blood proteins that work with antibodies during an immune response.