To sign on the opposite side of (a document).
To add a second signature to a document, affirming the validity of the signature of another person.
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 keep erect; to support; to sustain; to keep from falling
To hold up; to lift on high; to elevate.
To support by approval or encouragement, to confirm (something which has been questioned)