Как по Английски будет gegenzeichen

noun

An additional mark placed on something already marked, especially for increased security.

Примеры использования:

Any earlier coins that show a countermark do not indicate a date when later coins were countermarked.

verb

Add a signature to (a document already signed by another person).

Примеры использования:

Each cheque had to be signed and countersigned

noun

A signal or password given in reply to a soldier on guard.

Примеры использования:

Advance, patrol, and give the countersign to me