postal code vs postcode

postal code and postcode both are nouns.

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

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

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

Other synonyms of postal code include ZIP, ZIP code.

postal code (noun)	postcode (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