thermal \ther"mal\, a. l. thermae hot springs, fr. gr. ?, pl.
   of ? heat, fr. ? hot, warm, ? to warm, make hot; perhaps akin
   to l. formus warm, and e. forceps.
   1. of or pertaining to heat; warm; hot; as, the thermal unit;
      thermal waters.
      1913 webster

            the thermal condition of the earth.   --j. d.
                                                  forbes.
      1913 webster

   2. caused by or affected by heat; as, thermal springs.
      pjc

   3. designed to retain heat; as, thermal underwear.
      pjc

   thermal conductivity, thermal spectrum. see under
      conductivity, and spectrum.

   thermal unit physics, a unit chosen for the comparison or
      calculation of quantities of heat. the unit most commonly
      employed is the amount of heat necessary to raise the
      temperature of one gram or one pound of water from zero to
      one degree centigrade. see calorie, and under unit.
      1913 webster
see also:
thermal conductivity thermal spectrum conductivity spectrum thermal unit calorie 
unit 

thermal
     adj 1: relating to or associated with heat; "thermal movements of
            molecules"; "thermal capacity"; "thermic energy"; "the
            caloric effect of sunlight" syn: thermic, caloric
            ant: nonthermal
     2: of or relating to hot a hot spring; "thermal water"
     3: caused by or designed to retain heat; "a thermal burn";
        "thermal underwear"
     n : rising current of warm air
see also:
thermic caloric nonthermal 

26 moby thesaurus words for "thermal":
   aestival, blood-hot, blood-warm, calid, equatorial, fire storm,
   genial, hot air, luke, lukewarm, mild, room-temperature,
   subtropical, summery, sunny, sunshiny, superheated air, temperate,
   tepid, thermic, toasty, tropical, unfrozen, warm, warm as toast,
   warmish