photopigment

noun

Etymology: Etymology tree Proto-Indo-European *bʰeh₂- Proto-Indo-European *bʰéh₂os Proto-Hellenic *pʰáwos Ancient Greek φᾰ́ος (phắos) Ancient Greek φῶς (phôs) Ancient Greek φωτο- (phōto-)der. English photo- English pigment English photopigment From photo- + pigment.

1. Any pigment that is unstable in the presence of light; used especially of the chromophore pigments in the rod cells and cone cells of the eye