postmark

noun

1. A marking made by a postal service on a delivery, usually indicating the place where and the date and time when the item was received or processed for the first time, mostly serving to cancel a postage stamp.

   “He looked at the mauve envelope doubtfully, and examined the postmark. "Where is Pudlington, James? and one might almost ask—why is Pudlington? No town has any right to such an offensive name."”

verb

1. (transitive)To apply a postmark on.