Jetty

1. Made of jet, or like jet in color.
2. To jut out; to project.
3. A wharf or pier extending from the shore.
4. A part of a building that jets or projects beyond the rest, and overhangs the wall below.
5. A structure of wood or stone extended into the sea to influence the current or tide, or to protect a harbor; a mole; as, the Eads system of jetties at the mouth of the Mississippi River.