from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A class of organic compounds having a five-membered heterocyclic ring with two double bonds.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of a class of five-membered unsaturated heterocycles having three carbon atoms, one nitrogen atom and two double bonds
from the GNU version of the Collaborative International Dictionary of English
- n. Any of a large class of compounds characterized by a five-membered ring which contains an atom of nitrogen and at least one other noncarbon atom (nitrogen, oxygen, sulphur). The prefixes furo-, thio, and pyrro- are used to distinguish three subclasses of azoles, which may be regarded as derived respectively from furfuran, thiophene, and pyrrol by replacement of the CH group by nitrogen. Names exactly analogous to those for the azines are also used
from The Century Dictionary and Cyclopedia
- n. A general name given to a class of carbon-compounds containing a five-membered heteroatomic ring in which at least one atom is nitrogen, as pyrazole. oxazole, thiazole (which see).
Sorry, no etymologies found.