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.-any tree yielding tacamahac resin, especially, in north america, the balsam poplar, or balm of gilead (populus balsamifera).