Reticle

A reticle (or reticule) is a net of fine lines or fibers in the eyepiece of a sighting device, such as a telescope, a telescopic sight, a microscope, or the screen of an oscilloscope. The word reticle comes from the Latin "reticulum," meaning "net." Today, engraved lines or embedded fibers may be replaced by a computer-generated image superimposed on a screen or eyepiece. The term graticule is the synonymous term from French, coming from the Latin craticula for gridiron. Both may be used to describe any set of lines used for optical measurement, but in modern use the term reticle is most commonly used for gunsights and such, while graticule is more widely used for the covers of oscilloscopes and similar roles.