1. official marks stamped on mail by a post office, showing the date and place of mailing
Usage: plural of postmark

1. stamps mail with an official mark showing the date and place of mailing
Usage: third person singular present tense

Examples

• The old letters had faded postmarks from different cities.
• Collectors often look for rare postmarks on vintage envelopes.
• The postmarks showed the package had traveled across three states.
• She examined the postmarks to determine when each letter was sent.
• The postal worker postmarks hundreds of letters each day.
• The machine automatically postmarks all outgoing mail.
• Clear postmarks help track the mail delivery process.