Entry 1 sense Webster, 1913 Pentadecatoic /(pĕn`tȧ*dĕk`ȧ*tō"ĭk)/ · Pen·ta·dec·a·to·ic · IPA 01 a. Of, pertaining to, or derived from, pentadecane, or designating an acid related to it. 1. Of, pertaining to, or derived from, pentadecane, or designating an acid related to it.(Chem.)