downstage vs theater

downstage and theater both are nouns.

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

downstage (noun)	theater (noun)
the front half of the stage (as seen from the audience)	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

downstage (adjective)	theater (adjective)
of the front half of a stage

downstage (adverb)	theater (adverb)
at or toward the front of the stage