1. Any of several plants of the genus Solanum, such as the bittersweet nightshade, most of which have a poisonous juice.
2. Any of various similar or related plants, such as belladonna.

[Middle English, from Old English nihtscada : niht, night; see night + sceadu, shade.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.