Cognomen Demetro (Demetro 
) , all over the world, is a rare last name. The last name Demetro is characteristic of the United States, where it is a rare surname, Brazil, where it is a very rare surname, and New Zealand. In absolute terms, it is the most numerous in the United States, Brazil, and Spain. Very seldom, Demetro is the forename as well as the last name.