The story
From a method of testing vision by reading charts at a distance of 20 feet.
Etymology from Wiktionary, CC BY-SA 4.0.
twenty-twenty
Today it means: Having normal visual acuity. Full definition →
Today it means: Having normal visual acuity. Full definition →
From a method of testing vision by reading charts at a distance of 20 feet.
Etymology from Wiktionary, CC BY-SA 4.0.