printer vs compositor

printer and compositor both are nouns.

Word	Noun	Adjective	Verb	Adverb
printer	Yes	No	No	No
compositor	Yes	No	No	No

As nouns, compositor is a hyponym of printer; that is, compositor is a word with a more specific, narrower meaning than printer:

Other hyponyms of printer include setter, typesetter, typographer, proofreader, reader.

printer (noun)	compositor (noun)
a machine that prints	one who sets written material into type
(computer science) an output device that prints the results of data processing
someone whose occupation is printing