Twelfth-night :: Twelfth-night (n.) The evening of Epiphany, or the twelfth day after Christmas, observed as a festival by various churches..
Twelfth-second :: Twelfth-second (n.) A unit for the measurement of small intervals of time, such that 1012 (ten trillion) of these units make one second..
Twelfthtide :: Twelfthtide (n.) The twelfth day after Christmas; Epiphany; -- called also Twelfth-day.