retina

noun

ret·​i·​na ˈre-tə-nə 

ˈret-nə

plural retinas also retinae ˈre-tə-ˌnē 

-ˌnī

: the sensory membrane that lines the eye, is composed of several layers including one containing the rods and cones, and functions as the immediate instrument of vision by receiving the image formed by the lens and converting it into chemical and nervous signals which reach the brain by way of the optic nerve see eye illustration

Examples of retina in a Sentence

Recent Examples on the Web

When the cornea is clouded or scarred, the pathway is blocked even if the retina itself is healthy. —Charlie Fink, Forbes.com, 3 Sep. 2025

Indiana's offense is activated by his retina scan, though the lineups without him — those composed of players assembled with him in mind — hardly seemed to dip. —Alex Kirschenbaum, MSNBC Newsweek, 29 Aug. 2025

Light reflects off surfaces, passes through the cornea and lens, and lands on the retina, where photons trigger the photoreceptors that kick off neural processing. —Jonny Thomson, Big Think, 28 Aug. 2025

Researchers at The Jackson Laboratory (JAX) found that twisted and narrowed vessels in the retinas of mice with a common genetic mutation strongly resemble vascular abnormalities seen in Alzheimer’s patients. —Neetika Walter, Interesting Engineering, 26 Aug. 2025

Word History

Etymology

Middle English rethina, from Medieval Latin retina, probably from Latin rete net

First Known Use

14th century, in the meaning defined above

Kids Definition

retina

noun

ret·​i·​na ˈret-ᵊn-ə 

ˈret-nə

plural retinas also retinae -ᵊn-ˌē 

-ˌī

: the light-sensitive inner layer lining the back of the eye that contains the rods and cones and converts the images formed by the lens into signals which reach the brain by way of the optic nerve

retinal

-ᵊn-əl

-nəl

adjective

Medical Definition

retina

1 of 2 noun

ret·​i·​na ˈret-ᵊn-ə, ˈret-nə 

plural retinas also retinae -ᵊn-ˌē 

: the sensory membrane that lines most of the large posterior chamber of the vertebrate eye, is composed of several layers including one containing the rods and cones, and functions as the immediate instrument of vision by receiving the image formed by the lens and converting it into chemical and nervous signals which reach the brain by way of the optic nerve

Retin-A

2 of 2 trademark

Ret·​in-A ˌret-ᵊn-ˈā 

—used for a preparation of tretinoin