heat vs preheat

heat is a noun but preheat is not a noun.

Word	Noun	Adjective	Verb	Adverb
heat	Yes	No	Yes	No
preheat	No	No	Yes	No

As verbs, preheat is a hyponym of heat; that is, preheat is a word with a more specific, narrower meaning than heat:

Other hyponyms of heat include crisp, crispen, toast, scald, soak, calcine, overheat, scorch, sear, bake, broil, reheat.

heat (noun)	preheat (noun)
utility to warm a building
the presence of heat
the trait of being intensely emotional
the sensation caused by heat energy
a preliminary race in which the winner advances to a more important race
a form of energy that is transferred by a difference in temperature
applies to nonhuman mammals: a state or period of heightened sexual arousal and activity

heat (verb)	preheat (verb)
gain heat or get hot	heat beforehand
make hot or hotter
arouse or excite feelings and passions
provide with heat