Source : Webster's Revised Unabridged Dictionary (1913)

Alcanna \Al*can"na\, n. [Sp. alcana, alhe?a, fr. Ar.
   al-hinn[=a]. See {Henna}, and cf. {Alkanet}.] (Bot.)
   An oriental shrub ({Lawsonia inermis}) from which henna is
   obtained.