Source : Webster's Revised Unabridged Dictionary (1913)

Tacamahac \Tac"a*ma*hac`\, Tacamahaca \Tac`a*ma*ha"ca\, n.
   1. A bitter balsamic resin obtained from tropical American
      trees of the genus {Elaphrium} ({E. tomentosum} and {E.
      Tacamahaca}), and also from East Indian trees of the genus
      {Calophyllum}; also, the resinous exhudation of the balsam
      poplar.

   2. (Bot.) Any tree yielding tacamahac resin, especially, in
      North America, the balsam poplar, or balm of Gilead
      ({Populus balsamifera}).