a. - Made of jet, or like jet in color.
n. - A part of a building that jets or projects beyond the rest, and overhangs the wall below.
n. - A wharf or pier extending from the shore.
n. - 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.
v. i. - To jut out; to project.