The Collaborative International Dictionary of English v.0.48:

Iridoline \I*rid"o*line\, n. [Iridescent + L. oleum oil.]
   (Chem.)
   A nitrogenous base C10H9N, extracted from coal-tar naphtha,
   as an oily liquid. It is a member of the quinoline series,
   and is probably identical with lepidine. Iridosmine