Lammas \Lam"mas\, n. [AS. hl[=a]mmesse, hl[=a]fm[ae]sse, loaf mass, bread feast, or feast of first fruits; hl[=a]f loaf + m[ae]sse mass. See Loaf, and Mass religious service.]

The first day of August; -- called also Lammas day, and Lammastide.

Source: Webster's Revised Unabridged Dictionary (1913)