carotin vs carotene

carotin and carotene both are nouns.

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

As nouns, carotin and carotene are synonyms defined as:

carotin and carotene: an orange isomer of an unsaturated hydrocarbon found in many plants; is converted into vitamin A in the liver

Other synonyms of carotin include provitamin A.

carotin (noun)	carotene (noun)
an orange isomer of an unsaturated hydrocarbon found in many plants; is converted into vitamin A in the liver	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