What does "notary" mean?

Notary: (Eng. & Am. Law) A public officer who attests or certifies deeds and other writings, or copies of them, usually under his official seal, to make them authentic, especially in foreign countries. His duties chiefly relate to instruments used in commercial transactions, such as protests of negotiable paper, ship's papers in cases of loss, damage, etc. He is generally called a notary public.