orchestrator vs arranger

orchestrator and arranger both are nouns.

Word	Noun	Adjective	Verb	Adverb
orchestrator	Yes	No	No	No
arranger	Yes	No	No	No

As nouns, arranger is a hypernym of orchestrator; that is, arranger is a word with a broader meaning than orchestrator:

orchestrator: an arranger who writes for orchestras
arranger: a musician who adapts a composition for particular voices or instruments or for another style of performance

Other hypernyms of orchestrator include adapter, transcriber.

orchestrator (noun)	arranger (noun)
an arranger who writes for orchestras	a person who brings order and organization to an enterprise
	a musician who adapts a composition for particular voices or instruments or for another style of performance