thiazole

noun

1. Any of a class of unsaturated heterocyclic compounds containing a ring of three carbon atoms, a sulphur and a nitrogen atom; especially the simplest one, C₃H₃SN

   “Many heterocyclic bodies prepared synthetically have been manufactured upon a technical scale, because of their coloring and therapeutic properties. This is true of the dyes of [...] the thiazole-group, and also of the important febrifuges, [...]”