sumac (n.) Look up sumac at Dictionary.com
also sumach, c.1300, "preparation of dried, chopped leaves of a plant of the genus Rhus" (used in tanning and dyeing and as an astringent), from Old French sumac (13c.), from Medieval Latin sumach, from Arabic summaq, from Syrian summaq "red." Of the tree itself from 1540s; later applied to a North American plant species.