grocer (n.)

early 15c. (mid-13c. as a surname), "wholesale dealer, one who buys and sells in gross," corrupted spelling of Anglo-French grosser, Old French grossier, from Medieval Latin grossarius "wholesaler," literally "dealer in quantity" (source also of Spanish grosero, Italian grossista), from Late Latin grossus "coarse (of food), great, gross" (see gross (adj.)). Sense of "a merchant selling individual items of food" is 16c.; in Middle English this was a spicer.