An authorized signatory is an individual who has legal power to sign an official document on behalf of someone else, according to The Law Dictionary. Authorized signatories also sometimes act on behalf of businesses to commit to binding agreements, notes BusinessDictionary.com.
Individuals who act as authorized signatories typically are named to the position by an authorized individual or group, BusinessDictionary.com notes. An appointment of an individual as an authorized signatory may be on a permanent basis or for specific purposes of temporary duration. The Law Dictionary notes that acting as an authorized signatory can include acting as power of attorney, signing documents in place of someone else and witnessing legal documents.