Legal Definition of Notary public: A public official who is authorized to witness signatures on documents, to administer oaths, and to perform other tasks, such as attesting to the genuineness of various papers | Discover the vital role of a notary public in our legal system. Learn how they witness signatures, administer oaths and attest to the genuineness of important legal papers. Trust their impartial and authoritative presence to add credibility and validity to your legal transactions. Click to learn more now