heat

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A form of energy associated with the motion of atoms or molecules and capable of being transmitted through solid and fluid media by conduction, through fluid media by convection, and through empty space by radiation.
2. n. The transfer of energy from one body to another as a result of a difference in temperature or a change in phase.
3. n. Physics The sensation or perception of such energy as warmth or hotness.
4. n. Physics An abnormally high bodily temperature, as from a fever.
5. n. The condition of being hot.
6. n. A degree of warmth or hotness: The burner was on low heat.
7. n. The warming of a room or building by a furnace or another source of energy: The house was cheap to rent, but the heat was expensive.
8. n. A furnace or other source of warmth in a room or building: The heat was on when we returned from work.
9. n. Physics A hot season; a spell of hot weather.
10. n. Intensity, as of passion, emotion, color, appearance, or effect.
11. n. The most intense or active stage: the heat of battle.
12. n. A burning sensation in the mouth produced by spicy flavoring in food.
13. n. Physics Estrus.
14. n. Physics One of a series of efforts or attempts.
15. n. Sports & Games One round of several in a competition, such as a race.
16. n. A preliminary contest held to determine finalists.
17. n. Informal Physics Pressure; stress.
18. n. Slang An intensification of police activity in pursuing criminals.
19. n. Slang The police. Used with the.
20. n. Slang Physics Adverse comments or hostile criticism: Heat from the press forced the senator to resign.
21. n. Slang Physics A firearm, especially a pistol.
22. v. To make warm or hot.
23. v. To excite the feelings of; inflame.
24. v. To increase the molecular or kinetic energy of (an object).
25. v. To become warm or hot.
26. v. To become excited emotionally or intellectually.
27. heat up Informal To become acute or intense: "If inflation heats up, interest rates could increase” ( Christian Science Monitor).

Century Dictionary and Cyclopedia

1. n. A sensation of the kind produced by close proximity to fire. The sensation of heat is commonly described as opposite in character to that of cold; but, strictly considered, this opposition lies not so much in these sensations themselves as in their causes and associations. Like cold, the sensation of heat probably resides only in special points of the skin, the points sensitive to heat being different in location from those which are sensitive to cold.
2. n. That condition of a material body which is capable of producing the sensation of heat; in physics, the corresponding specific form of energy, consisting in an agitation of the molecules of matter, and measured by the total kinetic energy of such agitation. See energy, 7. Heat is of two kinds—heat proper, resident in a body, and radiant heat, which, from the physical point of view, is not properly heat at all, but, like light, a form of wave-motion projected by the vibrations of the luminiferous ether. Heat was formerly believed to be caused by an indestructible material fluid, called caloric. It is now known to be not a substance, but the energy of molecular motion, consisting, in the case of a gas, of nearly uniform rectilinear motions, with sudden changes of direction and velocity when the molecules come near enough to one another; in the case of a liquid, of irregular wanderings of its molecules; and in the case of a solid, of orbital or oscillatory motions. This motion entirely ceases only at the absolute zero point. The temperature is in fact nothing but the amount of heat per molecule. The effects of absorbed heat upon a body are: Increase of temperature—that is, increase of the heat of each molecule. To a limited extent this can be measured by the senses, but more accurately by thermometers (see thermometer), the thermopile, etc. Expansion, or increase of volume (see expansion). Change of state, as of a solid to a liquid (see fusion and liquefaction), or of a liquid to a gas (see vaporization). Thus, to transform ice at 0° C. into water (melt it), or water at 100° C. into vapor or steam, a large amount of heat is required. This heat disappears as sensible heat, and is said to become latent. Latent heat, however, is a misleading term, for it is not true that heat is latent as such, but only that so much heat-energy has been expended in changing the position of the molecules and overcoming their mutual attractions. If the process is reversed, this latent heat becomes sensible, as, for example, when steam is condensed in a steam-radiator. Heat also produces electrical effects (see electricity), and is instrumental in initiating chemical changes. Heat may be transmitted from one place to another— By convection (see convection), when the hot body is itself moved, as in heating by hot air conveyed in flues, or by hot water carried in pipes. By conduction (see conduction), where the heat travels slowly through the mass of the body, as when one end of an iron bar is thrust into the fire and the other end gradually becomes heated. In this case it is the molecular motion of the iron which is propagated. By radiation (see radiation). When heat was believed to be a substance, the radiation of heat was explained, in a manner analogous to the abandoned emission theory of light (see light), as the actual transfer of the heat-fluid itself; now, however, radiant heat is known to be the energy of heat transferred to the luminiferous ether (sec ether), which fills all space and also pervades all bodies. The hot body sets the ether-particles in vibration, and this vibratory motion, in the form of waves, travels in all directions and with a velocity of about 186,000 miles per second. If this radiant heat impinges upon a body, part of it may be absorbed, or, in other words, the molecules of the body may themselves be set in motion by the ether-waves. There is no essential difference between radiant heat and light, both being forms of radiant energy (see energy), the ether-waves differing intrinsically among themselves in wave-length only, and thus producing different effects, heating, luminous, and chemical, in the bodies upon which they impinge, according to the nature of these bodies. The rays whose heating effect is generally the greatest are of greater wave-length than those which most affect the eye (light-rays), and have longer periods of vibration. Like light-rays, they may be reflected, refracted, diffracted, and polarized. The quantity of heat of a body, or the amount of heat-energy which a body gains or loses in passing through a given range of temperature, is measured in thermal units (see heat-unit)—that is, by the quantity of water which it would raise through 1° C. (or 1° F.); it is given by the product of its weight into the number expressing the range in temperature multiplied by the specific heat. In ordinary speech heat and temperature are not distinguished. See temperature.
3. n. In ordinary use, a sensibly high temperature, as the warmth of the sun, or of the body.
4. n. A heating, as of a piece of iron to be wrought by a blacksmith, or of a mass of metal to be melted in a furnace; an exposure to intense heat.
5. n. Hence Violent action; high activity; intense and uninterrupted effort: as, to do a thing at a heat.
6. n. Especially— A single course in a horse-race or other contest.
7. n. A division of a race or contest when the contestants are too numerous to run at once, the race being finally decided by the winners (or winners and seconds) of each division running a final race or heat.
8. n. Indication of high temperature, as the condition or color of the body or part of the body; redness; high color.; flush.
9. n. Vehemence; rage; violence; excitement; animation; fervency; ardor; zeal: as, the heat of battle or of argument; the heat of passion or of eloquence.
10. n. Sexual desire or excitement in animals, especially in the female, corresponding to rut in the male; the period or duration of such excitement: as, to be in heat.
11. To cause to grow warm; communicate heat to; make hot: as, to heat an oven or a furnace; to heat iron. See heat, n., 2.
12. To make feverish; stimulate; excite: as, to heat the blood.
13. To warm with emotion, passion, or desire; rouse into action; animate; encourage.
14. To run a heat over, as in a race.
15. To grow warm or hot; come to a heated condition, from the effect either of something external or of chemical action, as in fermentation or decomposition.
16. n. The quantity or weight of metal undergoing a metallurgical process. See heat. 4.
17. n. In electricity, that portion of the heat developed in an electric circuit which cannot be converted directly into electrie energy. The total heat in an electric circuit is HJ= IRt + PIt, where H is the heat in calories, J is the mechanical equivalent, I the current, R the resistance, t the time during which the current flows, and P is the difference of potential due to the heating of any metal junctions that may exist in the circuit. The term IRt represents the irreversible heat. Also called ohmic heat. Compare reversible heat.
18. n. The heat in calories required to convert a gram of liquid at its melting-point into saturated vapor at a given pressure.

Wiktionary

1. v. To cause an increase in temperature of an object or space; to cause something to become hot; often with "up".
2. v. To arouse, to excite (sexually).
3. n. uncountable Thermal energy.
4. n. uncountable The condition or quality of being hot.
5. n. uncountable An attribute of a spice that causes a burning sensation in the mouth.
6. n. uncountable A period of intensity, particularly of emotion.
7. n. uncountable An undesirable amount of attention.
8. n. uncountable, slang The police.
9. n. uncountable, slang One or more firearms.
10. n. countable, baseball A fastball.
11. n. uncountable A condition where a mammal is aroused sexually or where it is especially fertile and therefore eager to mate.
12. n. countable A preliminary race, used to determine the participants in a final race
13. n. countable One cycle of bringing metal to maximum temperature and working it until it is too cool to work further
14. n. countable A hot spell.
15. n. uncountable Heating system.
16. n. uncountable The output of a heating system.

GNU Webster's 1913

1. n. 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.
2. n. 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.
3. n. High temperature, as distinguished from low temperature, or cold
4. n. 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.
5. n. A single complete operation of heating, as at a forge or in a furnace.
6. n. A violent action unintermitted; a single effort; a single course in a race that consists of two or more courses.
7. n. Utmost violence; rage; vehemence.
8. n. Agitation of mind; inflammation or excitement; exasperation.
9. n. Animation, as in discourse; ardor; fervency.
10. n. (Zoöl.) Sexual excitement in animals; readiness for sexual activity; estrus or rut.
11. n. Fermentation.
12. n. slang Strong psychological pressure, as in a police investigation.
13. v. To make hot; to communicate heat to, or cause to grow warm.
14. v. To excite or make hot by action or emotion; to make feverish.
15. v. To excite ardor in; to rouse to action; to excite to excess; to inflame, as the passions.
16. v. To grow warm or hot by the action of fire or friction, etc., or the communication of heat.
17. v. To grow warm or hot by fermentation, or the development of heat by chemical action.
18. Obs. or Archaic Heated.

WordNet 3.0

1. n. the sensation caused by heat energy
2. n. applies to nonhuman mammals: a state or period of heightened sexual arousal and activity
3. v. arouse or excite feelings and passions
4. v. gain heat or get hot
5. v. make hot or hotter
6. n. the trait of being intensely emotional
7. v. provide with heat
8. n. the presence of heat
9. n. a form of energy that is transferred by a difference in temperature
10. n. utility to warm a building
11. n. a preliminary race in which the winner advances to a more important race