/rooh"bahrb/ , n.
1. any of several plants belonging to the genus Rheum, of the buckwheat family, as R. officinale, having a medicinal rhizome, and R. rhabarbarum, having edible leafstalks.
2. the rhizome of any medicinal species of this plant, forming a combined cathartic and astringent.
3. the edible, fleshy leafstalks of R. rhabarbarum, used in making pies, preserves, etc.
4. Slang. a quarrel or squabble.
[ 1350-1400; ME rubarb, reubarb r ( e ) ubarbe reubarbarum rhéon bárbaron foreign rhubarb ]