naf'tha or nap'tha, the name first given to the mineral oil now known as petroleum, and now used to include most of the inflammable liquids produced in distilling animal or vegetable substances. Petroleum is now sometimes called native or mineral naphtha. Another liquid produced by the distillation of bog-head coal, is known as bog-head naphtha. The name is also applied in a general way to the light liquids formed in the distillation of petroleum and used in the manufacture of varnishes. These are divided into gasoline, benzine and naphtha, of which naphtha is the heaviest and contains the largest proportion of oil. This naphtha is sometimes sold under the name of petroleum spirit or petroleum ether. See PETROLEUM.