The Lesser Antilles, also known as the Caribbees, "West Indies." Merriam-Webster's Geographical Dictionary, 3rd ed. 2001. (ISBN 0-87779-546-0) Springfield, MA: Merriam-Webster Inc., p. 1298. are part of the Antilles, which together with the Bahamas and Greater Antilles form the West Indies. The islands are part of a long volcanic island arc, most of which wraps around the eastern end of the Caribbean Sea on the western boundary with the Atlantic Ocean, and some of which lies on the southern fringe of the sea just north of South America. The Lesser Antilles more or less coincide with the outer edge of the Caribbean Plate, and many of the islands were formed by subduction, as one or more other plates slipped under the Caribbean Plate.