ZIP vs postal code

ZIP and postal code both are nouns.

Word	Noun	Adjective	Verb	Adverb
ZIP	Yes	No	No	No
postal code	Yes	No	No	No

As nouns, ZIP and postal code are synonyms defined as:

ZIP and postal code: a code of letters and digits added to a postal address to aid in the sorting of mail

Other synonyms of ZIP include postcode, ZIP code.

ZIP (noun)	postal code (noun)
a code of letters and digits added to a postal address to aid in the sorting of mail	a code of letters and digits added to a postal address to aid in the sorting of mail