turret

A small tower or tower-shaped projection on a building.

A low, heavily armored structure, usually rotating horizontally, containing mounted guns and their gunners or crew, as on a warship or tank.

A domelike gunner’s enclosure projecting from the fuselage of a combat aircraft.

A tall wooden structure mounted on wheels and used in ancient warfare by besiegers to scale the walls of an enemy fortress.

An attachment for a lathe consisting of a rotating cylindrical block holding various cutting tools.

A rotating device holding various lenses, as for a microscope, allowing easy switching from one lens to another.

An attachment to a lathe, drill, boring-machine, or slotting-machine designed to hold and present to the work a series of boring-, drilling-, or cutting-tools, the object being to save the time lost in changing from one tool to another by hand.

A little tower rising from or otherwise connected with a larger building; a small tower, often crowning or finishing the angle of a wall, etc.