The Collaborative International Dictionary of English v.0.48:

ethane \eth"ane\ ([e^]th"[=a]n), n. [From Ether.] (Chem.)
   A gaseous hydrocarbon, C2H6, forming a constituent of
   ordinary illuminating gas. It is the second member of the
   paraffin series, and its most important derivatives are
   common alcohol (ethyl alcohol), acetaldehyde, ether, and
   acetic acid. Called also dimethyl.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ethane
    n 1: a colorless odorless alkane gas used as fuel [syn:
         ethane, C2H6]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "ethane":
   alcohol, benzine, briquette, burnable, butane, carbon, charcoal,
   coal, coke, combustible, dope, ethanol, fireball, firing,
   flammable, flammable material, fuel, fuel additive, fuel dope, gas,
   gas carbon, gasoline, heptane, hexane, inflammable,
   inflammable material, isooctane, jet fuel, kerosene, methane,
   methanol, natural gas, octane, oil, paraffin, peat, pentane,
   rocket fuel, turf