n The totality, the full amount or number which completes something. (defdate|from 16th c.)
n (obsolete) Something which completes one's equipment, dress etc.; an accessory. (defdate|16th-17th c.)
n (heraldry)fullness | Fullness (of the moon). (defdate|from 17th c.)
n (astronomy|geometry) An angle which, together with a given angle, makes a right angle. (defdate|from 18th c.)
n 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. (defdate|from 19th c.)
n (grammar) 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. (defdate|from 19th c.)
n (music) An interval which, together with the given interval, makes an octave. (defdate|from 19th c.)
n (optics) The color which, when mixed with the given color, gives black (for mixing pigments) or white (for mixing light). (defdate|from 19th c.)
n (set theory) 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). (defdate|from 20th c.)
n (logic) An expression related to some other expression such that it is true under the same conditions that make other false, and vice versa. (defdate|from 20th c.)
n (electronics) A voltage level with the opposite logical sense to the given one.
n (computing) A bit with the opposite value to the given one; the logical complement of a number.
n (genetics) A nucleotide sequence in which each base is replaced by the complementary base of the given sequence: adenine (A) by thymine (T) or uracil (U), cytosine (C) by guanine (G), and vice versa.