1. A cancellation mark stamped on mail by postal officials; indicates the post office and date of mailing
   "The postmark showed that the letter had been mailed three weeks ago"

1. Stamp with a postmark to indicate date and time of mailing
   "The post office postmarked all outgoing letters";
   - frank

Derived forms: postmarking, postmarks, postmarked

Type of: mark, marker, marking, stamp

Encyclopedia: Postmark