therm

from WordNet (r) 3.0 (2006)

therm
    n 1: a unit of heat equal to 100,000 British thermal units

from The Collaborative International Dictionary of English v.0.48

Therm \Therm\ (th[~e]rm), n.
   one of several units of heat, especially one equivalent to
   1000 large calories, or 100,000 British thermal units.
   [PJC]