carotenoid vs carotene

carotenoid and carotene both are nouns.

Word	Noun	Adjective	Verb	Adverb
carotenoid	Yes	No	No	No
carotene	Yes	No	No	No

As nouns, carotene is a hyponym of carotenoid; that is, carotene is a word with a more specific, narrower meaning than carotenoid:

carotenoid: any of a class of highly unsaturated yellow to red pigments occurring in plants and animals
carotene: yellow or orange-red fat-soluble pigments in plants

Other hyponyms of carotenoid include lycopene, beta-carotene, lutein, xanthophyl, xanthophyll, zeaxanthin.

carotenoid (noun)	carotene (noun)
any of a class of highly unsaturated yellow to red pigments occurring in plants and animals	an orange isomer of an unsaturated hydrocarbon found in many plants; is converted into vitamin A in the liver
	yellow or orange-red fat-soluble pigments in plants