The Collaborative International Dictionary of English v.0.48:

Solanine \Sol"a*nine\, n. [L. solanum nightshade.] (Chem.)
   A poisonous alkaloid glucoside extracted from the berries of
   common nightshade (Solanum nigrum), and of bittersweet, and
   from potato sprouts, as a white crystalline substance having
   an acrid, burning taste; -- called also solonia, and
   solanina.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Nightshade \Night"shade`\, n. [AS. nichtscadu.] (Bot.)
   A common name of many species of the genus Solanum, given
   esp. to the Solanum nigrum, or black nightshade, a low,
   branching weed with small white flowers and black berries
   reputed to be poisonous.
   [1913 Webster]

   Deadly nightshade. Same as Belladonna
   (a) .

   Enchanter's nightshade. See under Enchanter.

   Stinking nightshade. See Henbane.

   Three-leaved nightshade. See Trillium.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Solanum nigrum
    n 1: Eurasian herb naturalized in America having white flowers
         and poisonous hairy foliage and bearing black berries that
         are sometimes poisonous but sometimes edible [syn: black
         nightshade, common nightshade, poisonberry, poison-
         berry, Solanum nigrum]