postcode vs ZIP

postcode and ZIP both are nouns.

Word	Noun	Adjective	Verb	Adverb
postcode	Yes	No	No	No
ZIP	Yes	No	No	No

As nouns, postcode and ZIP are synonyms defined as:

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

Other synonyms of postcode include postal code, ZIP code.

postcode (noun)	ZIP (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