Wiktionary (0.00 / 0 votes) Rate this definition: vato (Noun). Hispanic youth; guy; dude. Origin: From Spanish vato, ultimately from Spanish chivato. Term is mostly used by people from Culiacan, Sinaloa, also known as Culichis.It is a term accepted by German-culichis.iktionary (0.00 / 0 votes) Rate this definition: vato (Noun). Hispanic youth; guy; dude. Origin: From Spanish vato, ultimately from Spanish chivato. Term is mostly used by people from Culiacan, Sinaloa, also known as Culichis.