[1] : The Collaborative International Dictionary of English v.0.48

coal \coal\ k=ol, n. as. col; akin to d. kool, ohg. chol,
   cholo, g. kohle, icel. kol, pl., sw. kol, dan. kul; cf. skr.
   jval to burn. cf. kiln, collier.
   1. a thoroughly charred, and extinguished or still ignited,
      fragment from wood or other combustible substance;
      charcoal.
      1913 webster

   2. min. a black, or brownish black, solid, combustible
      substance, dug from beds or veins in the earth to be used
      for fuel, and consisting, like charcoal, mainly of carbon,
      but more compact, and often affording, when heated, a
      large amount of volatile matter.
      1913 webster

   note: this word is often used adjectively, or as the first
         part of self-explaining compounds; as, coal-black; coal
         formation; coal scuttle; coal ship. etc.
         1913 webster

   note: in england the plural coals is used, for the broken
         mineral coal burned in grates, etc.; as, to put coals
         on the fire. in the united states the singular in a
         collective sense is the customary usage; as, a hod of
         coal.
         1913 webster

   age of coal plants. see age of acrogens, under acrogen.
      

   anthracite or glance coal. see anthracite.

   bituminous coal. see under bituminous.

   blind coal. see under blind.

   brown coal or brown lignite. see lignite.

   caking coal, a bituminous coal, which softens and becomes
      pasty or semi-viscid when heated. on increasing the heat,
      the volatile products are driven off, and a coherent,
      grayish black, cellular mass of coke is left.

   cannel coal, a very compact bituminous coal, of fine
      texture and dull luster. see cannel coal.

   coal bed geol., a layer or stratum of mineral coal.

   coal breaker, a structure including machines and machinery
      adapted for crushing, cleansing, and assorting coal.

   coal field geol., a region in which deposits of coal
      occur. such regions have often a basinlike structure, and
      are hence called coal basins. see basin.

   coal gas, a variety of carbureted hydrogen, procured from
      bituminous coal, used in lighting streets, houses, etc.,
      and for cooking and heating.

   coal heaver, a man employed in carrying coal, and esp. in
      putting it in, and discharging it from, ships.

   coal measures. geol.
      a strata of coal with the attendant rocks.
      b a subdivision of the carboniferous formation, between
          the millstone grit below and the permian formation
          above, and including nearly all the workable coal beds
          of the world.

   coal oil, a general name for mineral oils; petroleum.

   coal plant geol., one of the remains or impressions of
      plants found in the strata of the coal formation.

   coal tar. see in the vocabulary.

   to haul over the coals, to call to account; to scold or
      censure. colloq.

   wood coal. see lignite.
      1913 webster
see also:
kiln collier age of coal plants age of acrogens acrogen anthracite 
glance coal bituminous coal bituminous blind coal blind 
brown coal brown lignite lignite caking coal cannel coal 
coal bed coal breaker coal field coal basins basin 
coal gas coal heaver coal measures coal oil coal plant 
coal tar to haul over the coals wood coal 

[2] : WordNet (r) 2.0

coal gas
     n : gaseous mixture produced by distillation of bituminous coal
         and used for heating and lighting

Coal Gas >> C Words
Coal Gas, definition of term: Coal Gas
coal+gas_pag1.html

Coal >> C Words
Coal, definition of term: Coal
coal_pag1.html

Coal Scuttle >> C Words
Coal Scuttle, definition of term: Coal Scuttle
coal+scuttle_pag1.html

Coal Miner >> C Words
Coal Miner, definition of term: Coal Miner
coal+miner_pag1.html

Bituminous Coal >> B Words
Bituminous Coal, definition of term: Bituminous Coal
bituminous+coal_pag1.html

Anthracite Coal >> A Words
Anthracite Coal, definition of term: Anthracite Coal
anthracite+coal_pag1.html