(dē-hī'drō-kō-les'tĕr-ol), A zoosterol in skin and other animal tissues that on activation by ultraviolet light becomes antirachitic and is then referred to as cholecalciferol (vitamin D3). Synonym(s): provitamin D3
7-dehydrocholesterol
(dē-hī″drō-kŏ-les′tĕ-rol″) A steroid precursor of vitamin D that converts to the vitamin when skin is exposed to sunlight.