Lammas is traditionally observed on 1 August as an English harvest festival.
The name Lammas comes from the Old English hlāfmæsse, meaning loaf-mass. The date marked the beginning of the grain harvest, and bread made from the new wheat could be brought to church for blessing. In this sense, Lammas connected agricultural work with a Christian seasonal calendar.
Historically, 1 August was also associated with quarter days and legal or economic arrangements in parts of England. Customs varied from place to place, and Lammas was not a single standardized festival with identical ceremonies everywhere.
Lammas is sometimes confused with Lughnasadh, a Gaelic seasonal festival held around the same time. The dates overlap, but the names and cultural traditions are distinct. Modern pagan and folkloric communities may use Lammas for a broader first-harvest observance, while the historical English term specifically points to the loaf-blessing tradition.