1. Anything which is bittersweet.
3. (Science: botany) a climbing shrub, with oval coral-red berries (solanum dulcamara); woody nightshade. The whole plant is poisonous, and has a taste at first sweetish and then bitter. The branches are the officinal dulcamara. An American woody climber (Celastrus scandens), whose yellow capsules open late in autumn, and disclose the red aril which covers the seeds; also called Roxbury waxwork.