lu·te·in 
(ltē-ĭn, -tēn′)
(ltē-ĭn, -tēn′)n.
1. A yellow-orange xanthophyll carotenoid, C40H56O2, that occurs naturally in green plants and in the fat of plant-eating animals, egg yolk, the corpus luteum, and the retina, and that may help to prevent macular degeneration.
2. A dried preparation of corpus luteum.
[Latin lūteum, yellow, egg yolk (from neuter of lūteus, yellow, from lūtum, yellowweed) + -IN.]