Source : Webster's Revised Unabridged Dictionary (1913)

Water gas \Wa"ter gas`\ (Chem.)
   See under {Gas}.



   {Gas fitter}, one who lays pipes and puts up fixtures for
      gas.

   {Gas fitting}.
      (a) The occupation of a gas fitter.
      (b) pl. The appliances needed for the introduction of gas
          into a building, as meters, pipes, burners, etc.

   {Gas fixture}, a device for conveying illuminating or
      combustible gas from the pipe to the gas-burner,
      consisting of an appendage of cast, wrought, or drawn
      metal, with tubes upon which the burners, keys, etc., are
      adjusted.

   {Gas generator}, an apparatus in which gas is evolved; as:
      (a) a retort in which volatile hydrocarbons are evolved by
          heat;
      (b) a machine in which air is saturated with the vapor of
          liquid hydrocarbon; a carburetor;
      (c) a machine for the production of carbonic acid gas, for
          a["e]rating water, bread, etc. --Knight.

   {Gas jet}, a flame of illuminating gas.

   {Gas machine}, an apparatus for carbureting air for use as
      illuminating gas.

   {Gas meter}, an instrument for recording the quantity of gas
      consumed in a given time, at a particular place.

   {Gas retort}, a retort which contains the coal and other
      materials, and in which the gas is generated, in the
      manufacture of gas.

   {Gas stove}, a stove for cooking or other purposes, heated by
      gas.

   {Gas tar}, coal tar.

   {Gas trap}, a drain trap; a sewer trap. See 4th {Trap}, 5.

   {Gas washer} (Gas Works), an apparatus within which gas from
      the condenser is brought in contact with a falling stream
      of water, to precipitate the tar remaining in it.
      --Knight.

   {Gas water}, water through which gas has been passed for
      purification; -- called also {gas liquor} and {ammoniacal
      water}, and used for the manufacture of sal ammoniac,
      carbonate of ammonia, and Prussian blue. --Tomlinson.

   {Gas well}, a deep boring, from which natural gas is
      discharged. --Raymond.

   {Gas works}, a manufactory of gas, with all the machinery and
      appurtenances; a place where gas is generated for lighting
      cities.

   {Laughing gas}. See under {Laughing}.

   {Marsh gas} (Chem.), a light, combustible, gaseous
      hydrocarbon, {CH4}, produced artificially by the dry
      distillation of many organic substances, and occurring as
      a natural product of decomposition in stagnant pools,
      whence its name. It is an abundant ingredient of ordinary
      illuminating gas, and is the first member of the paraffin
      series. Called also {methane}, and in coal mines, {fire
      damp}.

   {Natural gas}, gas obtained from wells, etc., in
      Pennsylvania, Ohio, and elsewhere, and largely used for
      fuel and illuminating purposes. It is chiefly derived from
      the Coal Measures.

   {Olefiant gas} (Chem.). See {Ethylene}.

   {Water gas} (Chem.), a kind of gas made by forcing steam over
      glowing coals, whereby there results a mixture of hydrogen
      and carbon monoxide. This gives a gas of intense heating
      power, but destitute of light-giving properties, and which
      is charged by passing through some volatile hydrocarbon,
      as gasoline.

Source : WordNet®

water gas
     n : a mixture of hydrogen and carbon monoxide with small amounts
         of other gases; made by blowing steam over hot coke or
         coal