<p><strong>Adjective:</strong></p><ul><li>Both bitter and sweet to the taste: bittersweet chocolate.</li><li>Both pleasant and painful or regretful: a bittersweet memory.</li></ul><p><strong>Noun:</strong></p><ul><li>Also called woody nightshade: a climbing or trailing plant, <em>Solanum dulcamara</em>, of the nightshade family, having small, violet, star-shaped flowers with a protruding yellow center and scarlet berries.</li><li>Also called climbing bittersweet: any climbing plant of the genus <em>Celastrus</em>, bearing orange capsules opening to expose red-coated seeds, especially <em>C. scandens</em>.</li><li>Pleasure mingled with pain or regret: the bittersweet of parting.</li></ul>