The Collaborative International Dictionary of English v.0.48:

Thermic \Ther"mic\, a. [Gr. ? heat.]
   Of or pertaining to heat; due to heat; thermal; as, thermic
   lines.
   [1913 Webster]

   Thermic balance. See Bolometer.

   Thermic fever (Med.), the condition of fever produced by
      sunstroke. See Sunstroke.

   Thermic weight. (Mech.) Same as Heat weight, under
      Heat.
      [1913 Webster]

WordNet (r) 3.0 (2006):

thermic fever
    n 1: sudden prostration due to exposure to the sun or excessive
         heat [syn: sunstroke, insolation, thermic fever,
         siriasis]