Coun`ter*sign" Countersigning.] [Counter- + sign: cf. F. contresigner.]
To sign on the opposite side of (an instrument or writing); hence, to sign in addition to the signature of a principal or superior, in order to attest the authenticity of a writing.
© Webster 1913.
Coun"ter*sign`, a.
1.
The signature of a secretary or other officer to a writing signed by a principal or superior, to attest its authenticity.
2. Mil.
A private signal, word, or phrase, which must be given in order to pass a sentry; a watchword.
© Webster 1913.