nightshade: n. any of various poisonous plants, esp. of the genus Solanum, including S. nigrum (black nightshade) with black berries, and S. dulcamara (woody nightshade) with red berries. ødeadly nightshade = BELLADONNA. [OE nihtscada app. formed as NIGHT + SHADE, prob. with ref. to its poisonous properties]
