<p><strong>Noun</strong></p><ul><li>any of several plants belonging to the genus <em>Rheum</em>, of the buckwheat family, as <em>R. officinale</em>, having a medicinal rhizome, and <em>R. rhabarbarum</em>, having edible leafstalks.</li><li>the rhizome of any medicinal species of this plant, forming a combined cathartic and astringent.</li><li>the edible, fleshy leafstalks of <em>R. rhabarbarum</em>, used in making pies, preserves, etc.</li><li>Slang: a quarrel or squabble.</li></ul>