An island off the shore of a larger, central, or main island; specifically the inhabited islands of the Scilly Isles other than the main island of St Mary's.
Late 19th century ; earliest use found in Margaret Courtney (1834–1920). From off- + island.
Off or away from an island.
Not belonging to an island; done, produced, owned, etc. off an island.
Early 20th century. From off + island. Compare earlier off-islander.