postage stamp
small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage
en-GB/ˈpəʊstɪd͡ʒ ˈstæmp/
en-US/ˈpoʊstəd͡ʒ ˈstæmp/
small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage