Origin: From the unsupervised breeding of horses in unfrequented fields. Regional Note: Old-field colt is one of several old-fashioned regional euphemisms for a child born out of wedlock. The term is native to the Virginia Piedmont. Old-field is the Southern term for an overcultivated field allowed to lie fallow. Being isolated and usually undisturbed, these fields provided a place for unplanned breeding of horses and, figuratively, of children. The term is sometimes shortened to field colt. A related Southern expression is woods colt. The Western U.S. equivalent is catch colt.