heat

1 heat /ˈhiːt/ noun
plural heats
1 heat
/ˈhiːt/
noun
plural heats
Britannica Dictionary definition of HEAT
1 
[noncount] : energy that causes things to become warmer
2 
[noncount] : hot weather or temperatures
— often used with the
3 
a  : the level of temperature that is used to cook something
[count]
— usually singular
[noncount]
b  [singular] : a source of heat used for cooking something : the hot part of an oven, stove top, etc.
4 
[noncount] chiefly US : the system that is used to provide warmth to a room or building
5 
[noncount]
a  : strong and often angry feelings
b  : the time when emotions are most strongly felt — used in phrases like in the heat of passion, in the heat of the moment, etc.
— see also in the heat of (the) battle at 1battle
6 
chiefly US, informal
a  the heat : pressure to do something
◊ The expression if you can't stand/take the heat, get out of the kitchen means that you should not try to do a difficult job if you cannot deal with the pressure and problems that are part of the job.
b  [noncount] : criticism or abuse
7 
[count] : one of several races or contests that are held in order to decide who will be in the final race or contest
— see also dead heat

in heat

(US) or British on heat
— used to describe a female animal that is ready to have sex and is able to become pregnant

more heat than light

◊ To produce or generate more heat than light means to cause anger without helping to make something better understood.

pack heat

US slang, old-fashioned + humorous

— heatless

/ˈhiːtləs/ adjective
2 heat /ˈhiːt/ verb
heats; heated; heating
2 heat
/ˈhiːt/
verb
heats; heated; heating
Britannica Dictionary definition of HEAT
[+ object]
: to cause (something) to become warm or hot

heat up

[phrasal verb]
1 
: to become warm or hot
2 
: to become more active, intense, or angry
3 
heat (something) up or heat up (something) : to cause (something) to become warm or hot — see also preheat