To add a second signature to a document, affirming the validity of the signature of another person.
To sign on the opposite side of (a document).
A second signature added to a document to affirm the validity of the signature of the first person.
The response to a sign or signal.
To ratify; to make valid.
To penalize (a state etc.) with sanctions.
To give official authorization or approval to; to countenance.
An approval, by an authority, generally one that makes something valid.
A penalty, punishment, or some coercive measure, intended to ensure compliance; especially one adopted by several nations, or by an international body.
A law, treaty, or contract, or a clause within a law, treaty, or contract, specifying any of the above.