[su.mac] also su.mach n [ME sumac, fr. MF, fr. Ar summaq] (14c) 1: a material used in tanning and dyeing that consists of dried powdered leaves and flowers of various sumacs
2: any of a genus (Rhus) of trees, shrubs, and woody vines of the cashew family that have pinnately compound leaves turning to brilliant colors in the autumn, dioecious flowers, spikes or loose clusters of red or whitish berries, and in some cases foliage poisonous to the touch--compare poison ivy, poison oak