Certain established festivals or holidays in the ecclesiastical calendar. These days were anciently used as the dates of legal instruments, and in England the quarter-days, for paying rent, are four feast-days. The terms of the courts, in England, before 1875, were fixed to begin on certain days determined with reference to the occurrence of four of the chief feasts.
FEASTS
TheLaw.com Law Dictionary & Black's Law Dictionary 2nd Ed.