"kept in stock by a druggist," c.1720, from French officinal, from Medieval Latin officinalis, literally "of or belonging in an officina," a storeroom (of a monastery) for medicines and necessaries, in classical Latin "workshop, manufactory, laboratory," contraction of *opificina, from opifex (genitive opificis) "worker, workman, maker, doer" (from opus "work;" see opus) + -fex, -ficis "one who does," from facere "do, perform" (see factitious). Related: Officinally.