revenue stamp; stamp
A stamp affixed to documents to show payment of a tax or fee, such as on contracts or receipts.
契約書に印紙を貼る必要があります。
You need to affix a revenue stamp to the contract.
印紙税は文書に印紙を貼ることで納めます。
Stamp duty is paid by affixing a revenue stamp to the document.
I affixed a revenue stamp to the contract.
I bought a revenue stamp at the post office.