Question: do you have to graduate to have an alma mater

Answer: No, Alma mater (Latin: alma ``nourishing/kind'', mater ``mother''; pl. (rarely used) almae matres) is an allegorical Latin phrase for a university or college. In modern usage, it is a school or university which an individual has attended, or a song or hymn associated with a school. The phrase is variously translated as ``nourishing mother'', ``nursing mother'', or ``fostering mother'', suggesting that a school provides intellectual nourishment to its students. Fine arts will often depict educational institutions using a robed woman as a visual metaphor.