an official mark stamped on a letter or other postal package, giving the place, date, and time of posting, and serving to cancel the postage stamp 邮戳 the package had a York postmark. 这个包裹上有约克郡的邮戳。
verb
[with obj.](一般作 be postmarked)stamp (a letter or other postal package) officially with such a mark 在…上盖邮戳 [with obj. and complement]the letter was postmarked New York. 这封信上盖有纽约的邮戳。