heat barrier noun

Difficulties caused by a thin envelope of hot air which develops round aircraft at high speeds and causes structural and other problems

heat capacity same as thermal capacity (see under thermal).

heat death noun

The final state of the universe (if it is a closed system) predicted by the Second Law of Thermodynamics, in which heat and energy are uniformly distributed throughout the substance of the universe

heat engine noun

An engine that transforms heat into mechanical work

heatˈer-shield noun

A triangular shield, like the heated plate of an iron

heat exchanger noun

A device for transferring heat from one fluid to another without allowing contact between them

heat exhaustion noun

A condition caused by exposure to intense heat, characterized by dizziness, fatigue and abdominal pain

heatˈproof adjective

Resistant to or able to withstand heat

heat pump noun

A device (on the refrigerator principle) for drawing heat from water, air, or the earth, and giving it out to warm, eg a room

heatˈ-resistant adjective

heatˈ-seeking adjective

(of a missile) able to detect heat emitted by its target and home in on this

heat shield noun

An object or substance designed to protect against excessive heat, esp that which protects a spacecraft re-entering the earth's atmosphere

heat sink noun

Something into which unwanted heat can be directed

heatˈspot noun

1. An area of skin with nerve-ends sensitive to heat
2. A spot or blotch on the skin caused by heat
3. A freckle

heatˈstroke noun

1. Exhaustion, illness, or prostration due to exposure to heat
2. Sunstroke

heat treatment noun

1. The therapeutic use of heat in medicine
2. The use of heat in hardening metals

heatˈwave noun

1. A heated state of atmosphere passing from one locality to another
2. A hot spell

heat of formation (chem)

The net quantity of heat evolved or absorbed during the formation of one mole of a substance from its component elements in their standard states

in heat or on heat

(of a female animal) ready to mate

in the heat of the moment

While subject to passion and without pausing to think

latent heat

The heat required to change solid to liquid, or liquid to gas, without change of temperature

mechanical equivalent of heat

The energy required to produce one heat unit

specific heat see under specify

take the heat out of

To lessen the vehemence, intensity of emotion, or acrimony of (a situation, etc)

turn on the heat (informal)

To use brutal treatment, mental or physical, esp in order to coerce