Source : Webster's Revised Unabridged Dictionary (1913)

Oil \Oil\ (oil), n. [OE. oile, OF. oile, F. huile, fr. L. oleum;
   akin to Gr. ?. Cf. {Olive}.]
   Any one of a great variety of unctuous combustible
   substances, not miscible with water; as, olive oil, whale
   oil, rock oil, etc. They are of animal, vegetable, or mineral
   origin and of varied composition, and they are variously used
   for food, for solvents, for anointing, lubrication,
   illumination, etc. By extension, any substance of an oily
   consistency; as, oil of vitriol.

   Note: The mineral oils are varieties of petroleum. See
         {Petroleum}. The vegetable oils are of two classes,
         {essential oils} (see under {Essential}), and {natural
         oils} which in general resemble the animal oils and
         fats. Most of the natural oils and the animal oils and
         fats consist of ethereal salts of glycerin, with a
         large number of organic acids, principally stearic,
         oleic, and palmitic, forming respectively stearin,
         olein, and palmitin. Stearin and palmitin prevail in
         the solid oils and fats, and olein in the liquid oils.
         Mutton tallow, beef tallow, and lard are rich in
         stearin, human fat and palm oil in palmitin, and sperm
         and cod-liver oils in olein. In making soaps, the acids
         leave the glycerin and unite with the soda or potash.

   {Animal oil}, {Bone oil}, {Dipple's oil}, etc. (Old Chem.), a
      complex oil obtained by the distillation of animal
      substances, as bones. See {Bone oil}, under {Bone}.

   {Drying oils}, {Essential oils}. (Chem.) See under {Drying},
      and {Essential}.

   {Ethereal oil of wine}, {Heavy oil of wine}. (Chem.) See
      under {Ethereal}.

   {Fixed oil}. (Chem.) See under {Fixed}.

   {Oil bag} (Zo["o]l.), a bag, cyst, or gland in animals,
      containing oil.

   {Oil beetle} (Zo["o]l.), any beetle of the genus {Meloe} and
      allied genera. When disturbed they emit from the joints of
      the legs a yellowish oily liquor. Some species possess
      vesicating properties, and are used instead of
      cantharides.

   {Oil box}, or {Oil cellar} (Mach.), a fixed box or reservoir,
      for lubricating a bearing; esp., the box for oil beneath
      the journal of a railway-car axle.

   {Oil cake}. See under {Cake}.

   {Oil cock}, a stopcock connected with an oil cup. See {Oil
      cup}.

   {Oil color}.
   (a) A paint made by grinding a coloring substance in oil.
   (b) Such paints, taken in a general sense.