Source : Webster's Revised Unabridged Dictionary (1913)

Hound's-tongue \Hound's"-tongue`\, n. [AS. hundes tunge.] (Bot.)
   A biennial weed ({Cynoglossum officinale}), with soft
   tongue-shaped leaves, and an offensive odor. It bears nutlets
   covered with barbed or hooked prickles. Called also
   {dog's-tongue}.

Source : WordNet®

Cynoglossum officinale
     n : biennial shrub of Europe and western Asia having coarse
         tongue-shaped leaves and dark reddish-purple flowers
         [syn: {hound's-tongue}]