Main Entry: rho·dop·sin

Pronunciation: \rō-ˈdäp-sən\

Function: noun

Etymology: International Scientific Vocabulary rhod- + Greek opsis sight, vision + International Scientific Vocabulary ¹-in — more at optic

Date: 1886

: a red photosensitive pigment in the retinal rods of the eye of most vertebrates that is important in vision in dim light —called also visual purple