phen-ethyl-amine \fen-'eth-al-a-,men\ n。 [phenyl fr。 F。 phène, fr。 Gk。 phainein, to show (from its occurrence in illuminating gas)+ ethyl ( + yl) + amine fr。 NL ammonia] 1: A naturally occurring compound found in both the animal and plant kingdoms。 It is an endogenous component of the human brain。 2: Any of a series of compounds containing the phenethylamine skeleton, and modified by chemical constituents at appropriate positions in the molecule。