Learn how to say Countersigning correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word countersign:
a signature added to a document previously signed by another, for authentication or confirmation
a secret sign or signal in answer to another, as in a secret society
(military history) a secret word or signal which must be given to a guard or sentry by someone wishing to pass; password
to authenticate (a previously signed document) by adding one’s own signature