a bacterial growth factor, CHONS, present in all living things; vitamin H: it is one of the vitamin B group and is found in liver, egg yolk, yeast, etc.
See biotin in American Heritage Dictionary 4
(bīˈə-tĭn)
noun
A colorless crystalline vitamin, C10H16N2O3S, of the vitamin B complex, essential for the activity of many enzyme systems and found in large quantities in liver, egg yolk, milk, and yeast.