Source : Webster's Revised Unabridged Dictionary (1913)

Avens \Av"ens\, n. [OF. avence.] (Bot.)
   A plant of the genus {Geum}, esp. {Geum urbanum}, or herb
   bennet.

Source : WordNet®

avens
     n : any of various perennials of the genus Geum having usually
         pinnate basal leaves and variously colored flowers