Entry 1 sense Webster, 1913 Twelfthtide · Twelfth·tide · IPA /ˈtwɛlfθtaɪd/ 01 n. The twelfth day after Christmas; Epiphany; -- called also Twelfth-day. 1. The twelfth day after Christmas; Epiphany; -- called also Twelfth-day. Also: Twelfth-day