# vergence

> English word · Noun · IPA /ˈvɜː(ɹ)dʒəns/

## Definitions
1. The simultaneous turning of both eyes when focusing.
2. A measure of convergence or divergence of rays.
3. The direction of the overturned component of an asymmetric fold.

## Etymology
From verge (“tend, incline”, from Latin vergere) + -ence, synonym of earlier (1660s) vergency (the equivalent of French vergence). Coined as a technical term in ophthalmology, as a hypernym of convergence and divergence, in 1902. The sense of the numeric quantity in geometric optics was introduced, from use of the term in physiological optics, in the 1920s.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/vergence