(n)any of three isotopes of a colorless aromatic liquid hydrocarbon occurring in the volatile oil of cumin and thyme and used in the manufacture of synthetic resins
The Collaborative International Dictionary of English (GCIDE) v.0.53Collaborative International Dictionary (GCIDE)
n. (Chem.) A colorless, liquid, combustible hydrocarbon, CH3.C6H4.C3H7, of pleasant odor, obtained from oil of cumin, oil of caraway, carvacrol, camphor, etc.; -- called also paracymene, and formerly camphogen. [ 1913 Webster ]