Definition of: sumac

(s′mak, sh′-) noun
1. Any of a genus (Rhus) of woody, erect, or root–climbing plants (family Anacardiaceae), with panicles of small flowers, small drupaceous fruits, and yielding a resinous or milky juice; especially, the smooth sumac (R. glabra) used in medicine.
2. The poison sumac.
3. The dried and powdered leaves of certain species of sumac, used for tanning and dyeing, especially of tanner's sumac (Rhus coriaria). Also su′mach. [<OF <Med. L sumach <Arabic summāq]