ˌīəˈdäpsə̇n noun
( -s )
Etymology: iod- (from Greek ioeidēs violet-colored + ops- (from Greek opsis sight) + -in — more at iodine , -opsis
: a photosensitive violet pigment in the retinal cones of most animals that is similar to rhodopsin but more labile, that is formed from vitamin A 1 , and that is important in daylight vision