A turret is a small tower that sticks out from the wall of a building, usually at a corner. Castles often have turrets at their corners, giving defenders a place to watch for approaching enemies from multiple directions at once. These stone turrets sometimes had narrow windows called arrow slits where archers could shoot while staying protected.

The word also describes the rotating armored structure on top of a tank or warship that holds large guns. A tank's turret can spin 360 degrees, letting the gunner aim and fire in any direction without moving the entire vehicle. Battleships had massive turrets, some weighing hundreds of tons, that could rotate to aim their enormous guns at targets miles away.

You'll also find turrets on old locomotives and machine tools: any rotating part that holds tools or equipment and can turn to different positions. A metal lathe might have a turret holding several cutting tools that rotate into place when needed.

The key idea connecting these meanings is that a turret is something that projects outward or rotates to provide a better angle or position, whether for defense, attack, or precise work.