Any of various shrubs or small trees of the genus Rhus and other genera in Anacardiaceae, particularly the elm-leaved sumac, Sicilian sumac, or tanner's sumac (Rhus coriaria).

(transitive) To apply a preparation of sumac to (an object), for example, to a piece of leather to tan it.

A sweetened drink made with the drupes of the sumac.

(Internet slang, text messaging) someone