heat

n. & v.
—n.
1 a the condition of being hot. b the sensation or perception of this. c high temperature of the body.
2 Physics a a form of energy arising from the random motion of the molecules of bodies, which may be transferred by conduction, convection, or radiation. b the amount of this needed to cause a specific process, or evolved in a process (heat of formation; heat of solution).
3 hot weather (succumbed to the heat).
4 a warmth of feeling. b anger or excitement (the heat of the argument).
5 (foll. by of) the most intense part or period of an activity (in the heat of the battle).
6 a (usu. preliminary or trial) round in a race or contest.
7 the receptive period of the sexual cycle, esp. in female mammals.
8 redness of the skin with a sensation of heat (prickly heat).
9 pungency of flavour.
10 sl. intensive pursuit, e.g. by the police.
—v.
1 tr. & intr. make or become hot or warm.
2 tr. inflame; excite or intensify.
Phrases and idioms:
heat barrier the limitation of the speed of an aircraft etc. by heat resulting from air friction. heat capacity thermal capacity. heat death Physics a state of uniform distribution of energy to which the universe is thought to be tending. heat engine a device for producing motive power from heat. heat-exchanger a device for the transfer of heat from one medium to another. heat pump a device for the transfer of heat from a colder area to a hotter area by using mechanical energy. heat-resistant = HEATPROOF. heat-seeking (of a missile etc.) able to detect infrared radiation to guide it to its target. heat shield a device for protection from excessive heat, esp. fitted to a spacecraft. heat sink a device or substance for absorbing excessive or unwanted heat. heat-treat subject to heat treatment. heat treatment the use of heat to modify the properties of a metal etc. heat wave a period of very hot weather. in the heat of the moment during or resulting from intense activity, without pause for thought. on heat (of mammals, esp. females) sexually receptive. turn the heat on colloq. concentrate an attack or criticism on (a person).
Etymology: OE haeligtu f. Gmc