| 
 | 
Medical Definition of Vitamin D unit
1. The antirachitic activity contained in 0.025 ug of a preparation of crystalline vitamin D3 (activated 7-dehydrocholesterol). See: Steenbock unit. (05 Mar 2000)
| 
 | 
1. The antirachitic activity contained in 0.025 ug of a preparation of crystalline vitamin D3 (activated 7-dehydrocholesterol). See: Steenbock unit. (05 Mar 2000)