countersign

UK: /ˈkaʊntə^rsaɪn/

US: /ˈkaʊntɚˌsaɪn/

US: (n., v. koun′tər sīn′; v. also koun′tər sīn′)

WordReference Random House Learner's Dictionary of American English © 2025

coun•ter•sign /ˈkaʊntɚˌsaɪn/   n. [countable]

1. a sign used in reply to another sign.
2. a signature added to another signature, esp. to show that the first one is genuine.

v. [~ + object]

3. to sign (a document that has been signed by someone else), esp. in order to provide identification:
   Countersign the document where I've marked the lines with x's.

WordReference Random House Unabridged Dictionary of American English © 2025

coun•ter•sign  (n., v. koun′tər sīn′;v. also koun′tər sīn′), n. 

1. a sign used in reply to another sign.
2. Military a secret sign that must be given by authorized persons seeking admission through a guarded area.
3. a signature added to another signature, esp. for authentication.

v.t. 

4. to sign (a document that has been signed by someone else), esp. in confirmation or authentication.

• counter- + sign, modeled on Middle French contresigne, or its source, Old Italian contrasegno 1585–95

Collins Concise English Dictionary © HarperCollins Publishers::

countersign verb / ˈkaʊntəˌsaɪn ˌkaʊntəˈsaɪn/

1. (transitive) to sign (a document already signed by another)

noun / ˈkaʊntəˌsaɪn/

1. Also called: countersignature the signature so written
2. a secret sign given in response to another sign
3. a password