bore sight noun 2verb 1forms 3 noun2 •An optical device, mounted on or near the end of a firearm's barrel, used to align the sights with the bore. •A dummy cartridge containing a small battery-operated laser, used to align the sights. verb1 •To align the sights and aiming point of a firearm using a bore sight optical tool. formsbore sighted · bore sighting · bore sights