adj. Refers to an operator taking one operand. Compare binary, sense 4.

"One-way relation; pointer.Most relations are binary, which means they are automatically maintained both ways and can be traversed both ways."

An inefficient encoding system, in which the integer n is denoted by writing n 1's in sequence.

consisting of or involving a single element or component; "in a unary operation in a mathematical system one element is used to yield a single result"