unary

Etymology

From Latin ūnus (“one”) + -ary, on the pattern of binary, ternary, etc.

adj

1. Consisting of or involving a single element or component.
   Her work is a renunciation of the old narrative, a throwing away of the cotton reel, an enunciation of the unary signifier, fort, that is meaningless in itself. 1995, Becky McLaughlin, “Perverse Pleasure and Fetishized Text: The Deathly Erotics of Carter’s ‘The Bloody Chamber’”, in Style, volume 29, number 3, →JSTOR, page 219
2. (mathematics, programming, computer engineering) Of 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.
   Zadeh’s claim is that if the meaning of an expression (X) can be modeling by a fuzzy membership function variable, then the meaning of an expression such as “very X” is simply a membership function over the same variable determined by applying a unary operator to the membership function for X. 1990, Dominic A. Clark, “Verbal uncertainty expressions: A critical review of two decades of research”, in Current Psychology, volume 9, number 3, →DOI, page 229
   On the other hand, blank spaces should not be used for unary operators such as unary minus (−), address of (&), indirection (*), member access (.), increment (++), and decrement (−−). 2011, Robert Green, Henry Ledgard, “Coding Guidelines: Finding the Art in the Science”, in Communications of the ACM, volume 54, number 12, →DOI

noun

1. (mathematics) The unary, or bijective base-1, numeral system.
2. (information theory) Unary coding, an entropy encoding for natural numbers.