ˈpirəˌdēn, -_də̇n noun
( -s )
Etymology: pyr- + -id + -ine
: a toxic water-soluble flammable liquid heterocyclic base C 5 H 5 N that has a disagreeable odor, that is obtained by distillation of bone oil or now usually as a by-product of coking either by distillation of coal tar or by recovery from gas liquor, that is analogous to benzene in structure except that it contains a nitrogen atom and five carbon atoms in the ring, that is the parent of many naturally occurring organic compounds including alkaloids (as nicotine) and the vitamins nicotinamide and pyridoxine, and that is used chiefly as a solvent, as a denaturant for alcohol, and in the manufacture of pharmaceuticals (as antiseptics and antihistamine drugs) and waterproofing agents for textiles — compare piperidine , structural formula