heat
n. uncountablen. the quality of being hot or the high temperature of something. You feel this when you stand near a fire or in the sun.
n. the quality of being hot; high temperature. In a scientific context, it refers to the transfer of kinetic energy from one medium or object to another.
The heat from the sun feels good today.
The runners struggled to finish the race because of the intense afternoon heat and high humidity.
Engineers must design the spacecraft's outer shell to withstand the extreme heat generated by friction as the vessel re-enters the Earth's atmosphere at high speeds.
From Middle English hete, from Old English hǣtu, from Proto-West Germanic haitī, from Proto-Germanic haitį̄ (“heat”), from Proto-Indo-European *keHy- (“heat; hot”). Cognate with Scots hete (“heat”), Saterland Frisian Hatte (“heat”), Old High German heizī (“heat”). Related also to Dutch hitte (“heat”), German Hitze (“heat”), Swedish hetta (“heat”), Icelandic hiti (“heat”).
From Middle English heten, from Old English hǣtan (“to heat; become hot”), from Proto-Germanic *haitijaną (“to heat, make hot”).
Either an alternative spelling of het (“heated”), a continuation of late Middle English heet, het (an analogical simple past of heten (“to heat”) created on the basis of bet, the past tense of beten (“to beat”)), or a later analogical formation from the past forms of beten's modern reflex beat.
Commonly used with the definite article ('the heat') when referring to the weather or ambient temperature.