understand vs see

understand is not a noun while see is a noun.

Word	Noun	Adjective	Verb	Adverb
understand	No	No	Yes	No
see	Yes	No	Yes	No

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

As verbs, understand and see are synonyms defined as:

Other synonyms of understand include realise, realize.

understand (noun)	see (noun)
	the seat within a bishop's diocese where his cathedral is located

understand (verb)	see (verb)
know and comprehend the nature or meaning of	deem to be
perceive (an idea or situation) mentally	perceive (an idea or situation) mentally
believe to be the case	get to know or become aware of, usually accidentally
make sense of a language	be careful or certain to do something; make certain of something
be understanding of	deliberate or decide
	make sense of; assign a meaning to
	find out, learn, or determine with certainty, usually by making an inquiry or other effort
	match or meet
	receive as a specified guest
	imagine; conceive of; see in one's mind
	come together
	conduct someone someplace
	perceive by sight or have the power to perceive by sight
	perceive or be contemporaneous with
	see or watch
	see and understand, have a good eye
	observe as if with an eye
	undergo or live through a difficult experience
	observe, check out, and look over carefully or inspect
	date regularly; have a steady relationship with
	go to see a place, as for entertainment
	go to see for professional or business reasons
	go to see for a social visit
	take charge of or deal with