impression vs test copy

impression and test copy both are nouns.

Word	Noun	Adjective	Verb	Adverb
impression	Yes	No	No	No
test copy	Yes	No	No	No

As nouns, test copy is a hyponym of impression; that is, test copy is a word with a more specific, narrower meaning than impression:

Other hyponyms of impression include edition, proof, trial impression, mackle.

impression (noun)	test copy (noun)
an impressionistic portrayal of a person	(printing) an impression made to check for errors
the act of pressing one thing on or into the surface of another
(dentistry) an imprint of the teeth and gums in wax or plaster
an outward appearance
a vague idea in which some confidence is placed
a clear and telling mental image
a symbol that is the result of printing or engraving
all the copies of a work printed at one time
a concavity in a surface produced by pressing