a group of mostly marine, motile algae of the phylum Chlorophyta, characterized by the presence of the pigments chlorophyll, carotene, and xanthophyll, which impart golden to yellow-brown colors.
Also called xanthophyll. a yellow-red, water-insoluble, crystalline, carotenoid alcohol, C 40 H 56 O 2 , found in the petals of marigold and certain other flowers, egg yolk, algae, and corpora lutea: used chiefly in the biochemical study of the carotenoids.