noun

• (uncountable) Thermal energy.
  "Heat and temperature, although different, are intimately related. [...] For example, suppose you added equal amounts of heat to equal masses of iron and aluminum. How do you think their temperatures would change?[…]if the temperature of the iron increased by 100 C°, the corresponding temperature change in the aluminum would be only 48 C°."
• (uncountable) The condition or quality of being hot.
  "Stay out of the heat of the sun!"
• (uncountable) An attribute of a spice that causes a burning sensation in the mouth.
  "The chili sauce gave the dish heat."
• (uncountable) A period of intensity, particularly of emotion.
  "It's easy to make bad decisions in the heat of the moment."

verb

• (transitive) To cause an increase in temperature of (an object or space); to cause to become hot (often with "up").
  "I'll heat up the water."
• (intransitive) To become hotter.
  "There's a pot of soup heating on the stove."
• (transitive, figurative) To excite or make hot by action or emotion; to make feverish.
  "Ile leaue you my ſweete Ladie, for a while, pray walke ſoftly, doe not heate your bloud, what, I muſt haue care of you."
• (transitive, figurative) To excite ardour in; to rouse to action; to excite to excess; to inflame, as the passions.
  "A noble emulation heats your breaſt, / And your own fame now robs you of your reſt."

verb

• (dialectal or obsolete) simple past and past participle of heat
  "Then was Nebuchad-nezzár ful of rage, and the forme of his viſage was changed againſt Shadrách, Meſhach, & Abednegó: therefore he charged and commanded that they ſhulde heate the fornace at once ſeuen ⁱtimes more then it was wonte to be heate."

noun

• (military) Acronym of high explosive antitank, a munition using a high explosive shaped charge to breach armour.