[Lam.mas] n [ME Lammasse, fr. OE hlafmaesse, fr. hlaf loaf, bread + maesse mass; fr. the fact that formerly loaves from the first ripe grain were consecrated on this day] (bef. 12c) 1: August 1 orig. celebrated in England as a harvest festival--called also Lammas Day
2: the time of the year around Lammas Day