Island

1. A contiguous area of land, smaller than a continent, totally surrounded by water. We spent a week in the Hawaiian Islands.
2. An entity surrounded by other entities that are very different from itself. She was an island of tranquility.
3. A superstructure on an aircraft carriers deck. The ship's captain works in the island.
4. A raised structure in a road intersection to protect a police officer directing auto traffic. The traffic island was six feet high and made of concrete.