appear vs theater

appear is not a noun while theater is a noun.

Word	Noun	Adjective	Verb	Adverb
appear	No	No	Yes	No
theater	Yes	No	No	No

appear (noun)	theater (noun)
	a building where theatrical performances or motion-picture shows can be presented
	the art of writing and producing plays
	a region in which active military operations are in progress

appear (verb)	theater (verb)
come into sight or view
be issued or published
come into being or existence, or appear on the scene
appear as a character on stage or appear in a play, etc.
give a certain impression of being something or having a certain aspect
(of a proposition) seem to be true, probable, or apparent
present oneself formally, as before a (judicial) authority