stamp
US /stæmp/
UK /stæmp/

1.
a small adhesive piece of paper affixed to a letter or parcel to show that the postal charge has been paid
:
•
I need to buy a stamp for this letter.
•
The letter arrived with a rare commemorative stamp.
2.
1.
2.
3.
to affix a postage stamp to (a letter or parcel)
:
•
Don't forget to stamp the envelope before mailing it.
•
All outgoing mail must be properly stamped.