Postmark is an official mark printed over a postage stamp.

邮戳是印于邮票上的官方戳记。

youdao

There is an official mark of despair and an imperial affliction which is above and beyond the norm.

有在之上是和在准则之外绝望和皇家苦恼的一个正式标记。

youdao

An official mark, design, or seal that indicates ownership, approval, completion, or the payment of a tax.

官方戳记：一种官方标记，图案或者邮戳，表明主人，赞同，完成或付税。

youdao

And then there is the possibility that the central bank's presence as a shareholder in quoted companies will be interpreted by other investors as an official mark of approval.

ECONOMIST: Central banking

She also unveiled a plaque, covered with an animal feed bag, to mark the official opening.

BBC: Elephant habitat safari