adj made of jet, or like jet in color.
2. jetty ·noun a wharf or pier extending from the shore.
3. jetty ·vi to jut out; to project.
4. jetty ·noun a part of a building that jets or projects beyond the rest, and overhangs the wall below.
5. jetty ·noun 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.