Lammas, also known as Loaf Mass Day or Lughnasadh, is a Christian holiday celebrated on August 1st in some English-speaking countries. It marks the first harvest of the year, with a focus on giving thanks for the abundance of the harvest and the earth's fertility. The name "Lammas" originates from the Old English "hlāfmæsse," meaning "loaf mass," as the first loaves of the season were often blessed during mass.