island off the SE coast of Mass., south of Cape Cod: c. 100 sq mi (259 sq km)
Origin:
after a Martha Gosnold and the wild grapes growing there
See Martha's Vineyard in American Heritage Dictionary 4
An island of southeast Massachusetts off the southwest coast of Cape Cod. Settled in 1642, it was a whaling and fishing center in the 18th and early 19th centuries and is now a popular resort area.