Retina
noun ·Uncommon ·Advanced level
Definitions
- 1 The thin layer of cells at the back of the eyeball that contains rods and cones sensitive to light, which trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed.
- 2 the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve wordnet
Example
More examples"The image projected onto the retina is inverted."
Etymology
From Middle English rethina, borrowing from Medieval Latin rētīna (“retina”, feminine noun), ellipsis of tunica rētīna (“net-like tunic”), used to describe the blood vessel system at the back of the eye. The phrase is attested in the 12th century in Guillelmus the abbot and Gerard of Cremona—the latter may have created this phrase as a translation for Arabic طَبَقَة شَبَكِيَّة (ṭabaqa šabakiyya) "net-like layer", which translates Ancient Greek ἀμφιβληστροειδής χῐτών (amphiblēstroeidḗs khĭtṓn, “retina”), which is attested in the ancient medical writer Galen.
Related phrases
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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.