/ˈs(j)uːmæk/
noun
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).Dried and chopped-up leaves and stems of a plant of the genus Rhus, particularly the tanner's sumac (see sense 1), used for dyeing and tanning leather or for medicinal purposes.A sour spice popular in the Eastern Mediterranean, made from the berries of tanner's sumac.verb
To apply a preparation of sumac to (an object), for example, to a piece of leather to tan it.