1.AdjectiveConsisting of or involving a single element or component.
2.AdjectiveOf an operation, function, procedure, or logic gate, taking exactly one operand, argument, parameter, or input; having domain of dimension 1.
"Negation is a unary operation."
3.NounThe unary, or bijective base-1, numeral system.
4.NounUnary coding, an entropy encoding for natural numbers.