The Collaborative International Dictionary of English v.0.48:

Heat \Heat\ (h[e^]t), imp. & p. p. of Heat.
   Heated; as, the iron though heat red-hot. [Obs. or Archaic]
   --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Heat \Heat\ (h[=e]t), v. t. [imp. & p. p. Heated; p. pr. & vb.
   n. Heating.] [OE. heten, AS. h[=ae]tan, fr. h[=a]t hot. See
   Hot.]
   1. To make hot; to communicate heat to, or cause to grow
      warm; as, to heat an oven or furnace, an iron, or the
      like.
      [1913 Webster]

            Heat me these irons hot.              --Shak.
      [1913 Webster]

   2. To excite or make hot by action or emotion; to make
      feverish.
      [1913 Webster]

            Pray, walk softly; do not heat your blood. --Shak.
      [1913 Webster]

   3. To excite ardor in; to rouse to action; to excite to
      excess; to inflame, as the passions.
      [1913 Webster]

            A noble emulation heats your breast.  --Dryden.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Heat \Heat\, v. i.
   1. To grow warm or hot by the action of fire or friction,
      etc., or the communication of heat; as, the iron or the
      water heats slowly.
      [1913 Webster]

   2. To grow warm or hot by fermentation, or the development of
      heat by chemical action; as, green hay heats in a mow, and
      manure in the dunghill.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Heat \Heat\ (h[=e]t), n. [OE. hete, h[ae]te, AS. h[=ae]tu,
   h[=ae]to, fr. h[=a]t hot; akin to OHG. heizi heat, Dan. hede,
   Sw. hetta. See Hot.]
   1. A force in nature which is recognized in various effects,
      but especially in the phenomena of fusion and evaporation,
      and which, as manifested in fire, the sun's rays,
      mechanical action, chemical combination, etc., becomes
      directly known to us through the sense of feeling. In its
      nature heat is a mode of motion, being in general a form
      of molecular disturbance or vibration. It was formerly
      supposed to be a subtile, imponderable fluid, to which was
      given the name caloric.
      [1913 Webster]

   Note: As affecting the human body, heat produces different
         sensations, which are called by different names, as
         heat or sensible heat, warmth, cold, etc., according to
         its degree or amount relatively to the normal
         temperature of the body.
         [1913 Webster]

   2. The sensation caused by the force or influence of heat
      when excessive, or above that which is normal to the human
      body; the bodily feeling experienced on exposure to fire,
      the sun's rays, etc.; the reverse of cold.
      [1913 Webster]

   3. High temperature, as distinguished from low temperature,
      or cold; as, the heat of summer and the cold of winter;
      heat of the skin or body in fever, etc.
      [1913 Webster]

            Else how had the world . . .
            Avoided pinching cold and scorching heat! --Milton.
      [1913 Webster]

   4. Indication of high temperature; appearance, condition, or
      color of a body, as indicating its temperature; redness;
      high color; flush; degree of temperature to which
      something is heated, as indicated by appearance,
      condition, or otherwise.
      [1913 Webster]

            It has raised . . . heats in their faces. --Addison.
      [1913 Webster]

            The heats smiths take of their iron are a blood-red
            heat, a white-flame heat, and a sparkling or welding
            heat.                                 --Moxon.
      [1913 Webster]

   5. A single complete operation of heating, as at a forge or
      in a furnace; as, to make a horseshoe in a certain number
      of heats.
      [1913 Webster]

   6. A violent action unintermitted; a single effort; a single
      course in a race that consists of two or more courses; as,
      he won two heats out of three.
      [1913 Webster]

            Many causes . . . for refreshment betwixt the heats.
                                                  --Dryden.
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            [He] struck off at one heat the matchless tale of
            "Tam o' Shanter."                     --J. C.
                                                  Shairp.
      [1913 Webster]

   7. Utmost violence; rage; vehemence; as, the heat of battle
      or party. "The heat of their division." --Shak.
      [1913 Webster]

   8. Agitation of mind; inflammation or excitement;
      exasperation. "The heat and hurry of his rage." --South.
      [1913 Webster]

   9. Animation, as in discourse; ardor; fervency; as, in the
      heat of argument.
      [1913 Webster]

            With all the strength and heat of eloquence.
                                                  --Addison.
      [1913 Webster]

   10. (Zool.) Sexual excitement in animals; readiness for
       sexual activity; estrus or rut.
       [1913 Webster +PJC]

   11. Fermentation.
       [1913 Webster]

   12. Strong psychological pressure, as in a police
       investigation; as, when they turned up the heat, he took
       it on the lam. [slang]
       [PJC]

   Animal heat, Blood heat, Capacity for heat, etc. See
      under Animal, Blood, etc.

   Atomic heat (Chem.), the product obtained by multiplying
      the atomic weight of any element by its specific heat. The
      atomic heat of all solid elements is nearly a constant,
      the mean value being 6.4.

   Dynamical theory of heat, that theory of heat which assumes
      it to be, not a peculiar kind of matter, but a peculiar
      motion of the ultimate particles of matter.

   Heat engine, any apparatus by which a heated substance, as
      a heated fluid, is made to perform work by giving motion
      to mechanism, as a hot-air engine, or a steam engine.

   Heat producers. (Physiol.) See under Food.

   Heat rays, a term formerly applied to the rays near the red
      end of the spectrum, whether within or beyond the visible
      spectrum.

   Heat weight (Mech.), the product of any quantity of heat by
      the mechanical equivalent of heat divided by the absolute
      temperature; -- called also thermodynamic function, and
      entropy.

   Mechanical equivalent of heat. See under Equivalent.

   Specific heat of a substance (at any temperature), the
      number of units of heat required to raise the temperature
      of a unit mass of the substance at that temperature one
      degree.

   Unit of heat, the quantity of heat required to raise, by
      one degree, the temperature of a unit mass of water,
      initially at a certain standard temperature. The
      temperature usually employed is that of 0[deg] Centigrade,
      or 32[deg] Fahrenheit.
      [1913 Webster]

WordNet (r) 3.0 (2006):

heat
    n 1: a form of energy that is transferred by a difference in
         temperature [syn: heat, heat energy]
    2: the presence of heat [syn: hotness, heat, high
       temperature] [ant: cold, coldness, frigidity,
       frigidness, low temperature]
    3: the sensation caused by heat energy [syn: heat, warmth]
    4: the trait of being intensely emotional [syn: heat,
       warmth, passion]
    5: applies to nonhuman mammals: a state or period of heightened
       sexual arousal and activity [syn: estrus, oestrus,
       heat, rut] [ant: anestrum, anestrus, anoestrum,
       anoestrus]
    6: a preliminary race in which the winner advances to a more
       important race
    7: utility to warm a building; "the heating system wasn't
       working"; "they have radiant heating" [syn: heating system,
       heating plant, heating, heat]
    v 1: make hot or hotter; "the sun heats the oceans"; "heat the
         water on the stove" [syn: heat, heat up] [ant: chill,
         cool, cool down]
    2: provide with heat; "heat the house"
    3: arouse or excite feelings and passions; "The ostentatious way
       of living of the rich ignites the hatred of the poor"; "The
       refugees' fate stirred up compassion around the world"; "Wake
       old feelings of hatred" [syn: inflame, stir up, wake,
       ignite, heat, fire up]
    4: gain heat or get hot; "The room heated up quickly" [syn:
       heat, hot up, heat up] [ant: chill, cool, cool
       down]

Moby Thesaurus II by Grady Ward, 1.0:

282 Moby Thesaurus words for "heat":
   John Law, Le Mans, a transient madness, abandon, activate, agitate,
   agitation, air race, anger, angriness, animate, annoy, ardency,
   ardor, arousal, arouse, automobile race, awake, awaken, bake,
   barbecue, baste, bicycle race, blanch, blow the coals, blow up,
   boat race, boil, braise, brew, broil, brown, calenture, call forth,
   call up, chafe, childbed fever, coddle, commitment, committedness,
   contest of speed, continued fever, cook, cop, copper,
   cross-country race, curry, dash, dedication, delirium, derby,
   devil, devotedness, devotion, devoutness, do, do to perfection,
   dog race, drag race, eagerness, earnestness, ecstasy,
   electric-heat, endurance race, enkindle, enrage, enragement,
   enthusiasm, eruptive fever, estral cycle, estruation, estrum,
   estrus, excite, excitement, exhilaration, faith, faithfulness, fan,
   fan the fire, fan the flame, febricity, febrility, feed the fire,
   ferment, fervency, fervidness, fervor, fever, fever heat,
   fever of excitement, feverishness, fidelity, fieriness, fire,
   fire up, flame, flatfoot, flush, foment, footrace, frenzy,
   fricassee, frizz, frizzle, fry, furor, fury, fury of lust, fuzz,
   gas-heat, grapes of wrath, griddle, grill, gusto, heart,
   heartiness, heat up, heatedness, hectic, hectic fever,
   hectic flush, hot, hot up, hot-air-heat, hot-water-heat, hotness,
   hurdle race, hyperpyrexia, hyperthermia, ignite, impassion,
   impassionedness, impetuosity, incense, incite, inflame, infuriate,
   infuriation, inspirit, instigate, intensify, intensity, intentness,
   intermittent fever, irateness, ire, key up, kindle, lap, lather up,
   light the fuse, light up, liveliness, loyalty, mad, madden, man,
   marathon, marathon race, match race, motorcycle race, move, mull,
   nettle, obstacle race, oven-bake, overexcite, overheat, paddy, pan,
   pan-broil, parboil, passion, passionateness, peace officer, pique,
   poach, police, potato race, preheat, prepare, prepare food,
   protein fever, provoke, puerperal fever, put up to, pyrexia,
   quicken, race, rally, recook, regatta, reheat, relapsing fever,
   relay, relay race, relish, remittent, remittent fever, resolution,
   road race, roast, rouse, run, rut, sack race, saeva indignatio,
   saute, savor, scallop, sear, seriousness, set astir, set fire to,
   set on, set on fire, sexual excitement, shirr, sic on, simmer,
   sincerity, soreness, soul, speedway race, spirit, sprint,
   sprint race, steam, steam up, stew, stimulate, stimulation, stir,
   stir the blood, stir the embers, stir the feelings, stir up,
   stir-fry, stock-car race, stoke up, stress, summon up, superheat,
   tenseness, tension, tepefy, three-legged race, tickle, toast,
   torch race, torridity, torridness, track race, turn on,
   urethral fever, vaccinal fever, vehemence, verve, vials of wrath,
   wake, wake up, waken, walk, warm, warm over, warm the blood,
   warm up, warmness, warmth, warmth of feeling, water fever, whet,
   whip up, work into, work up, wound fever, wrath, wrathfulness,
   yacht race, zeal, zealousness



The Devil's Dictionary (1881-1906):

HEAT, n.

    Heat, says Professor Tyndall, is a mode
        Of motion, but I know now how he's proving
    His point; but this I know -- hot words bestowed
        With skill will set the human fist a-moving,
    And where it stops the stars burn free and wild.
    _Crede expertum_ -- I have seen them, child.
                                                          Gorton Swope