|a sight used for aiming a gun|
any of numerous optical devices that aid in aiming a firearm. Its forms include the simple iron sights on pistols and the more complex front and rear sights on target and high-powered sporting rifles. Front sights are usually fixed and rear sights movable so they can be adjusted both for elevation and for windage. When a bullet is fired, air resistance to its spin will warp its course slightly to the right or left, and gravity will pull it downward, producing a trajectory that will take the bullet below and slightly to one side of the point at which the gun barrel is "looking." Adjusting the sights so that the bullet will strike its target is called "laying" the firearm.
Learn more about gunsight with a free trial on Britannica.com.