Noun | 1. 0 - a mathematical element that when added to another number yields the same numbercypher, nought, zero, cipherdigit, figure - one of the elements that collectively form a system of numeration; "0 and 1 are digits" | Adj. | 1. 0 - indicating the absence of any or all units under consideration; "a zero score"zerocardinal - being or denoting a numerical quantity but not order; "cardinal numbers" |