the coastal region of the Americas along the Caribbean Sea; esp., the N coast of South America between the Isthmus of Panama & the mouth of the Orinoco: an earlier usage
later, the Caribbean Sea itself, or that part of it adjacent to the N coast of South America, traveled in the 16th-18th cent. by Spanish merchant ships, which were often harassed by pirates
See Spanish Main in American Heritage Dictionary 4
The coastal region of mainland Spanish America in the 16th and 17th centuries, extending from the Isthmus of Panama to the mouth of the Orinoco River.
The section of the Caribbean Sea crossed by Spanish ships in colonial times. The treasure-laden ships were often raided by English buccaneers.