The opposite of cold. Describes fire, furnaces, stoves and sex.

Fire exists in several forms. Things that burn do not always create a recognizable flame. Some substances burn at low temperatures, so low that they don't cause the air to glow, and so their flames are invisible. Invisible, and not terribly hot.

Then there's the hottest fire of all, the four state of matter, plasma. The sun is made of plasma so, propotionately, there's far more plasma in our solar system than rock, liquid or gas.

The sex enjoyed by the naked couple in the field that Jared drove past while fleeing his old life wasn't as hot as the sun. But it was close.