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}).