1. crosshairs or other marking patterns in the eyepiece of optical instruments used for precise aiming or measurement
Usage: technical; optics

Examples

• The sniper adjusted his scope until the target was centered in the reticles.
• The telescope’s reticles helped astronomers measure the precise position of stars.
• Modern rifle scopes feature illuminated reticles for better visibility in low light.
• The surveyor used the reticles in his transit to take accurate measurements.
• Different reticle patterns are available depending on the intended use of the scope.
• The microscope’s reticles allowed researchers to measure cellular structures precisely.