dinner theatre vs dinner theater

dinner theatre and dinner theater both are nouns.

Word	Noun	Adjective	Verb	Adverb
dinner theatre	Yes	No	No	No
dinner theater	Yes	No	No	No

As nouns, dinner theatre and dinner theater are synonyms defined as:

dinner theatre and dinner theater: a theater at which dinner is included in the price of admission

dinner theatre (noun)	dinner theater (noun)
a theater at which dinner is included in the price of admission	a theater at which dinner is included in the price of admission