(in New York City) Long Island (in New York State)

(in British Columbia) Vancouver Island

(UK, colloquial) HM Prison Parkhurst, a prison on the Isle of Wight.

A contiguous area of land, smaller than a continent, totally surrounded by water.

(by extension, in place names) A contiguous area of land, smaller than a continent, partially surrounded by water; A peninsula; A half-island.

An entity surrounded by other entities that are very different from itself.

A superstructure on an aircraft carrier's deck.

A traffic island.

(by extension, West Midlands dialect) A roundabout; A traffic circle.

A bench, counter, etc., that is not connected to a wall or other furniture and which can be used from any side.

(government) An unincorporated area wholly surrounded by one or more incorporated areas.

(grammar) A phrase from which a wh-word cannot be extracted without yielding invalid grammar.

(transitive) To surround with water; make into an island.

(transitive) To set, dot (as if) with islands.

(transitive) To isolate.