postage vs postage stamp

postage and postage stamp both are nouns.

Word	Noun	Adjective	Verb	Adverb
postage	Yes	No	No	No
postage stamp	Yes	No	No	No

As nouns, postage and postage stamp are synonyms defined as:

postage and postage stamp: a small adhesive token stuck on a letter or package to indicate that postal fees have been paid

Other synonyms of postage include stamp.

postage (noun)	postage stamp (noun)
a small adhesive token stuck on a letter or package to indicate that postal fees have been paid	a small adhesive token stuck on a letter or package to indicate that postal fees have been paid
the charge for mailing something