Vitamin C is water soluble.
So are the B-family of vitamins, and Vitamin B7 / Vitamin H (biotin).
Vitamins A, D, E and K are fat soluble.
By definition, vitamins are nutrients necessary for metabolic processes in the body. Plenty of "nutrients" (chemicals we also need to survive) are not vitamins, but are no less essential for life.
So are the B-family of vitamins, and Vitamin B7 / Vitamin H (biotin).
Vitamins A, D, E and K are fat soluble.
By definition, vitamins are nutrients necessary for metabolic processes in the body. Plenty of "nutrients" (chemicals we also need to survive) are not vitamins, but are no less essential for life.