The Collaborative International Dictionary of English v.0.48:

Methane \Meth"ane\, n. [See Methal.] (Chem.)
   A light, colorless, gaseous, inflammable hydrocarbon, CH4;
   marsh gas. It is the simplest of the aliphatic hydrocarbons.
   See Marsh gas, under Gas.
   [1913 Webster]

   Methane series (Chem.), a series of saturated hydrocarbons,
      of which methane is the first member and type, and
      (because of their general chemical inertness and
      indifference) called also the paraffin (little affinity)
      series. The lightest members are gases, as methane,
      ethane; intermediate members are liquids, as hexane,
      heptane, etc. (found in benzine, kerosene, etc.); while
      the highest members are white, waxy, or fatty solids, as
      paraffin proper.
      [1913 Webster]

WordNet (r) 3.0 (2006):

methane series
    n 1: a series of non-aromatic saturated hydrocarbons with the
         general formula CnH(2n+2) [syn: methane series, alkane
         series, alkane, paraffin series, paraffin]