Heat

Part of speech: noun, verb

Pronunciation: /hiːt/

Definitions

1. A form of energy that flows from warmer to cooler objects and can cause temperature changes or phase transitions in matter
2. A form of energy that produces a sensation of warmth, transfers between objects at different temperatures, and can lead to changes in the state of matter
3. A manifestation of energy that causes increased molecular motion, influences temperature variations, and can result in the transformation of substances from solid to liquid or gas

Etymology: The noun and the verb "heat" look like a matched pair, but they split off from different ancestors in English. The noun comes from Old English "hǣtu," a word that goes back to a Proto-Germanic root meaning simply warmth or hotness, and it is close kin to the German "Hitze," the Dutch "hitte," and the Swedish "hetta." The verb comes from Old English "hǣtan," meaning to make hot or become hot, and it shares that same root. Both forms have been related to the adjective "hot" from the start, so the family resemblance is old. The verb's past tense is the odd part. In Middle English the past tense of "heat" was "het," which is the form still seen in "het up," and that form probably came about by analogy with "bet," the past of "beat," rather than from any regular sound change. Over time "heated" took over as the usual past form, while "het" survived mainly as an adjective in phrases like "het up."

Synonyms: warmth, temperature, calor, intensity, fervor

Antonyms: cold, chill, coolness, frost, frigidity