A situation has reached a point of great commotion, energy, or activity.

(rare) Hot.

A system that raises the temperature of a room or building. Compare heater. / The act of making something hot.

Causing heat.

present participle of heat

(uncountable) Thermal energy. / (uncountable) The condition or quality of being hot. / (uncountable) An attribute of a spice that causes a burning sensation in the mouth.

(transitive) To cause an increase in temperature of (an object or space); to cause to become hot (often with "up"). / (intransitive) To become hotter.

Alternative form of in heat

simple past tense and past participle of heat up

simple past tense and past participle of steam-heat