Main Entry: ret·i·na

Pronunciation: \ˈre-tə-nə, ˈret-nə\

Function: noun

Inflected Form(s): plural retinas or ret·i·nae \-ˌnē, -ˌnī\

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

Date: 14th century

: 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