1) Carotene 2) Carotin 1) Hydrocarbon 2) Vitamin precursor 
A provitamin is a substance that may be converted within the body to a vitamin. The term `previtamin` is a synonym. For example, `Provitamin B5` is a name for Panthenol, which may be converted in the body to `Vitamin B5` a.k.a. Pantothenic Acid. The term `provitamin` is used when it is desirable to label a substance with little or no vitam...
(from the article `vitamin`) ...and cholecalciferol (vitamin D3). Vitamin D3 represents the dietary source, while vitamin D2 occurs in yeasts and fungi. Both can be formed from ...
A chemical that becomes a vitaminvia a natural reaction within anorganism, such as when 7-dehydrocholesterol in the skin becomes vitamin Dwhen its exposed to sunlight. ... (09 Oct 1997) ... 
(pro-vi´tә-min) a substance (such as ergosterol) from which an animal organism can form a vitamin.
Type: Term Pronunciation: prō-vī′tă-min Definitions: 1. A substance that can be converted into a vitamin; β-carotene.
[n] - vitamin precursor
noun vitamin precursor; a substance that is converted into a vitamin in animal tissues
Any precursor substance of a vitamin. Provitamins are ingested substances that become converted to active vitamins within the organism. One example is ergosterol (provitamin D2), which through the action of sunlight is converted to calciferol (vitamin D2); another example is beta-carotene, which...
a substance that an organism can transform into a vitamin, as carotene, which is converted to vitamin A in the liver.