| Noun | 1. 4 - the cardinal number that is the sum of three and oneIV, Little Joe, quadruplet, quartet, quatern, four, quaternion, quaternity, tetrad, foursome, quaternarydigit, figure - one of the elements that collectively form a system of numeration; "0 and 1 are digits" | Adj. | 1. 4 - being one more than three four, ivcardinal - being or denoting a numerical quantity but not order; "cardinal numbers" |