1976, D.A. Nordlund and W.J. Lewis. Terminology of chemical releasing stimuli in intraspecific and interspecific interactions. Journal of Chemical Ecology 2:211-220. (http://www.tifton.uga.edu/lewis/ab169.htm):
Allomone-- A substance, produced or acquired by an organism, which, when it contacts an individual of another species in the natural context, evokes in the receiver a behavioral or physiological reaction adaptively favorable to the emitter but not to the receiver.