Other forms: postmarks
A postmark is the stamped mark showing where and when it was posted. Check the postmark, a London postmark, postmarked yesterday.
It cancels the stamp so it cannot be used again, and it dates the letter, which is why courts and competitions rely on it: postmarked by a date is a legal test. Collectors study them, and a rare postmark can be worth more than the stamp under it.
1nounpostmarkThe stamped mark showing where and when it was posted.
“The postmark showed that the letter had been sent from Paris two weeks earlier.”
postmark is a mark.
Post plus mark, from the eighteenth century, when postal services began cancelling stamps.
Compound of post + mark.
Etymology from Wiktionary, CC BY-SA