Rio \rio\ as a boy's name is pronounced REE-oh. It is of Spanish origin, and the meaning of Rio is "river". Place name; independent name and short form of names ending with -rio. Rio de Janiero, Brazil, which means "January river" in Portuguese. The Rio Grande is the boundary river between Texas and Mexico, and its name means "big river" in Spanish.
Rio has 1 variant form: Reo.