Cognomen A-O (A-O 
) , in all the world, is a very rare family name. The last name A-O is characteristic of Morocco, where it is a very rare surname, Philippines, and Spain, where it is an extremely rare surname. Not in comparison with a country's population, it most frequently occurs in Philippines, Morocco, and China. Much less frequently, A-O is the forename as well as the last name. Parts of the name also exists independently as a first name A, and a last name O.