(computing) The number obtained by complementing every bit of a given number and adding one. A number and its complement add to 2ⁿ, where n is the word size of the machine.

The number which, added to the given n-digit number in radix r, results in rⁿ. In binary (r=2), this is the two's complement.

(computing) The number, obtained by complementing every bit of a given number, which produces all ones when exclusive ored with the given number.

(immunology) An aspect of the innate immune system that supplements the actions of the antibodies and phagocytic cells in clearing out pathogens from an organism

(mathematics) The relative pseudo-complement of a given element (of a Heyting algebra) with respect to the least element — the "zero" of that algebra.

(linear algebra, functional analysis) The set of all vectors which are orthogonal to a given set of vectors.

(biology) The air that can be drawn into the lungs in addition to the tidal air, by the deepest possible inhalation.

plural of complement system

(immunology) Any of a group of plasma proteins that bring about the destruction of pathogens through opsonization or assault on the cell membrane.

(regular expressions) Characters which are excluded in a pattern.