Noun | 1. 6 - the cardinal number that is the sum of five and oneCaptain Hicks, half a dozen, hexad, sestet, sextuplet, sise, six, sixer, VI, sextetdigit, figure - one of the elements that collectively form a system of numeration; "0 and 1 are digits" | Adj. | 1. 6 - denoting a quantity consisting of six items or unitshalf dozen, half-dozen, six, vicardinal - being or denoting a numerical quantity but not order; "cardinal numbers" |