Marcelo is the Spanish and Portuguese form of Marcellus which is an ancient Roman diminutive of Marcus. The name’s usage in North America is primarily driven by immigrants from South America to the United States (rather than those coming from Mexico). Many people consider Marcelo an Italian sounding name, but the Italians would typically spell it with two “L”s (Marcello) and pronounce it like “mahr-CHEL-lo”.