An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Sharpness; acuteness; keenness of perception.

M.E., from M.Fr. acuité, from M.L. acuitatem (nom. acuitas) "sharpness," from L. acus "needle," acuere "to sharpen," from PIE root *ak- "be sharp."

Tiznâ "sharpness," from tiz, "→ sharp," + -nâ, a suffix that transforms adjective into noun (compare with tangnâ, derâznâ, farâxnâ, etc.).

The ability of the → eye to see separately two points close to each other. It is a measure of the → resolving power of the eye's → optical system and depends on the density of cells in the → retina. The maximum acuity of the normal human eye is around 0.5 minutes of arc.

→ acuity; → vision.

Same as → acuity of vision.

→ visual; → acuity.