The Collaborative International Dictionary
heteroauxin
indoleacetic acid \in"dole*a*cet"ic ac"id\ ([i^]n"d[=o]l), n. (Chem., Bot.) A plant hormone ( C10H9NO2) recognized as the principle growth regulator in higher plants; called also heteroauxin. Abbreviated IAA. Chemically it is 1H-indole-3-acetic acid.
Wiktionary
heteroauxin
n. A growth promoting hormone, ''3-indoleacetic acid'', occurring in some plants.