passe-partout vs passkey

passe-partout and passkey both are nouns.

Word	Noun	Adjective	Verb	Adverb
passe-partout	Yes	No	No	No
passkey	Yes	No	No	No

As nouns, passe-partout and passkey are synonyms defined as:

Other synonyms of passe-partout include master, master key.

passe-partout (noun)	passkey (noun)
key that secures entrance everywhere	key that secures entrance everywhere
a mounting for a picture using gummed tape