A tail gunner or rear gunner is a crewman on a military aircraft who functions as a gunner defending against enemy fighter or interceptor attacks from the rear, or "tail", of the plane.
Tail gunner in a USAAF B-17 Flying Fortress, 1943
The Russian Sikorsky Ilya Muromets (model S-25 variant Geh-2, from March 1916) was the first aircraft equipped with a tail gun position
Vickers Virginia in flight
A row of Halifax bombers under assembly, 1942. Note the rounded turret position towards the end of the tail
A gun turret is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in some degree of azimuth and elevation.
A modern naval gun turret (A French 100 mm naval gun on the Maillé-Brézé pictured) allows firing of the cannons via remote control. Loading of ammunition is also often done by automatic mechanisms.
The commander's cupola of a Conqueror tank with a machine gun
BEP vignette In the Turret (engraved before 1863).
HMS Captain was one of the first ocean-going turret ships