1. A small tower or tower-shaped projection on a building.
2. 1. A low, heavily armored structure, usually rotating horizontally, containing mounted guns and their gunners or crew, as on a warship or tank.
   2. A domelike gunner's enclosure projecting from the fuselage of a combat aircraft.
3. A tall wooden structure mounted on wheels and used in ancient warfare by besiegers to scale the walls of an enemy fortress.
4. An attachment for a lathe consisting of a rotating cylindrical block holding various cutting tools.
5. A rotating device holding various lenses, as for a microscope, allowing easy switching from one lens to another.

[Middle English turet, from Old French torete, diminutive of tor, tower. See tower.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.