late 14c., from L., lit. "bountiful mother," title Romans gave to goddesses, especially Ceres and Cybele, from alma, fem. of almus "nourishing," from alere "to nourish" (see old) + mater "mother." First used 1710 in sense of "one's university or school" in ref. to British universities.
Alma Mater. The school or college one attended and, usually, graduated from, as in During football season I always check to see how my alma mater is doing. This expression sometimes refers to the institution's official song, as in I never did learn the words to my college's alma mater. The term is Latin for “kind mother.”
[ c. 1800