heat

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun 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.
• noun The transfer of energy from one body to another as a result of a difference in temperature or a change in phase.
• noun The sensation or perception of such energy as warmth or hotness.
• noun An abnormally high bodily temperature, as from a fever.
• noun The condition of being hot.
• noun A degree of warmth or hotness.
• noun The warming of a room or building by a furnace or another source of energy.
• noun A furnace or other source of warmth in a room or building.
• noun A hot season; a spell of hot weather.
• noun Intensity, as of passion, emotion, color, appearance, or effect.
• noun The most intense or active stage.
• noun A burning sensation in the mouth produced by spicy flavoring in food.
• noun Estrus.
• noun One of a series of efforts or attempts.
• noun Sports & Games One round of several in a competition, such as a race.
• noun A preliminary contest held to determine finalists.
• noun Informal Pressure; stress.
• noun An intensification of police activity in pursuing criminals.
• noun The police. Used with the.
• noun Slang Adverse comments or hostile criticism.
• noun Slang A firearm, especially a pistol.
• intransitive verb To make warm or hot.
• intransitive verb To excite the feelings of; inflame.
• intransitive verb Physics To increase the molecular or kinetic energy of (an object).
• intransitive verb To become warm or hot.
• intransitive verb To become excited emotionally or intellectually.

from The Century Dictionary.

• 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.
• To make feverish; stimulate; excite: as, to heat the blood.
• To warm with emotion, passion, or desire; rouse into action; animate; encourage.
• To run a heat over, as in a race.
• 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.
• noun The quantity or weight of metal undergoing a metallurgical process. See heat. 4.
• noun 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.
• noun The heat in calories required to convert a gram of liquid at its melting-point into saturated vapor at a given pressure.
• noun A sensation of the kind produced by close proximity to fire.
• noun 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.
• noun In ordinary use, a sensibly high temperature, as the warmth of the sun, or of the body.
• noun 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.
• noun Hence Violent action; high activity; intense and uninterrupted effort: as, to do a thing at a heat.
• noun Especially— A single course in a horse-race or other contest.
• noun 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.
• noun Indication of high temperature, as the condition or color of the body or part of the body; redness; high color.; flush.
• noun Vehemence; rage; violence; excitement; animation; fervency; ardor; zeal: as, the heat of battle or of argument; the heat of passion or of eloquence.