- sharpness; acuteness; keenness: acuity of vision; acuity of mind.
- keenness or acuteness, esp in vision or thought
- the capacity of the eye to see fine detail, measured by determining the finest detail that can just be detected
early 15c., from Middle French acuité (16c.) or directly from Medieval Latin acuitatem (nominative acuitas) “sharpness,” from Latin acuere “to sharpen,” related to acus “needle,” acuere “to sharpen,” from PIE root *ak- “rise to a point, be sharp” (see acrid).
- Sharpness, clearness, and distinctness of perception or vision.