biotin
n//ˈbaɪətɪn//biotin, vitamin B7
(vitamin) A sulfur-containing member of the vitamin B complex, 5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanoic acid, found in liver, egg yolk, milk, and yeast, essential to the activity of multiple enzyme systems.