provitamin
/ˈproʊ.vɪ.tɪ.nəm/Definitions
1. noun
A substance that can be converted into a vitamin in the body.
“Vitamin D2 is a provitamin that can be obtained from sunlight or certain foods.”
2. noun
Any organic compound that can be converted into a vitamin in the body, typically by oxidation, reduction, or other biochemical reactions.
“The plant contains several provitamins that are essential for human health.”