Lammas means Loaf Mass and is the start of the harvest period, and traditionally the time when the first loaf was baked.
Lammas is the festival of the dying and rising God, it is a time for sacrifices. In some cases the last sheaf of the harvest is sacrificed to the land in thanks for the bounty of the year. Some of the harvest corn is milled and made into either Gingerbread men, representing the God, or into a loaf of bread to be eaten and sacrificed. This Sabbat is sometimes referred to as loaf-mass.