tonga bean

from The Collaborative International Dictionary of English v.0.48

Tonka bean \Ton"ka bean`\ [Cf. F. onca, tonka.] (Bot.)
   The seed of a leguminous tree ({Dipteryx odorata}), native of
   Guiana. It has a peculiarly agreeable smell, and is employed
   in the scenting of snuff. Called also {tonquin bean}.
   [Written also {tonca bean}, {tonga bean}.]
   [1913 Webster]