Source : Webster's Revised Unabridged Dictionary (1913)

Boxthorn \Box"thorn`\, n. (Bot.)
   A plant of the genus {Lycium}, esp. {Lycium barbarum}.

Source : WordNet®

boxthorn
     n : any of various shrubs or vines of the genus Lycium with
         showy flowers and bright berries [syn: {matrimony vine}]