- to sign (a promissory note) in addition to the maker, thus becoming responsible for the obligation if the maker should default
- to sign jointly
transitive verbco·signed, co·sign·ing, co·signs
- To sign (a document) jointly.
- To endorse (another's signature), as for a loan.
(third-person singular simple present cosigns, present participle cosigning, simple past and past participle cosigned)
co- + sign
(third-person singular simple present co-signs, present participle co-signing, simple past and past participle co-signed)
- Alternative form of cosign.