define acuity
acuity - sharpness of vision; the visual ability to resolve fine detail (usually measured by a Snellen chart) sharp-sightedness, visual acuity. visual modality, visual sense, vision, sight - the ability to see; the visual faculty. 20/20, twenty-twenty - normal visual acuity, as measured by the ability to read charts at a distance of 20 feet. oxyopia - unusually acute vision. keenness, sharpness, acuteness.