Definition of: rhubarb

(r′bärb) noun
1. A stout, coarse, perennial herb (genus Rheum) of the buckwheat family, having large leaves and small clusters of flowers on tall fleshy stalks; especially, the common rhubarb or pie plant (R. rhaponticum), whose acid leaf stalks are used in cooking.
2. The dried roots of the medicinal rhubarb (R. officinale and R. palmatum), used as a cathartic and bitter tonic.
2. U.S. Slang A heated argument; scuffle or quarrel. [<OF reubarbe <LL rhabarbarum <Gk. Rha Volga river, Volga plant, rhubarb + barbaron foreign; so called because orig. imported from Russia]