Source : Webster's Revised Unabridged Dictionary (1913)

Pentane \Pen"tane\, n. [See {Penta-}.] (Chem.)
   Any one of the three metameric hydrocarbons, {C5H12}, of the
   methane or paraffin series. They are colorless, volatile
   liquids, two of which occur in petroleum. So called because
   of the five carbon atoms in the molecule.