adj. & n.
adj. 1 a dual. b of or involving pairs. 2 of the arithmetical system using 2 as a base.
n. (pl. -ies) 1 something having two parts. 2 a binary number. 3 a binary star. binary code Computing a coding system using the binary digits 0 and 1 to represent a letter, digit, or other character in a computer (see BCD). binary compound Chem. a compound having two elements or radicals. binary fission the division of a cell or organism into two parts. binary number (or digit) one of two digits (usu. 0 or 1) in a binary system of notation. binary star a system of two stars orbiting each other. binary system a system in which information can be expressed by combinations of the digits 0 and 1 (corresponding to 'off' and 'on' in computing). binary tree a data structure in which a record is branched to the left when greater and to the right when less than the previous record.
[ LL binarius f. bini two together ]