The twelfth day after Christmas; Epiphany; -- called also Twelfth-day.(noun)
Gnu Collaboartive International Dictionary of English: licensed under The Code Project Open License (CPOL)
Use "twelfthtide" in a sentence
"Christians, are derived the profane riots of new year's day, twelfthtide, and shrovetide, by which many pervert these times into days of sin and intemperance."