lumisterol
noun
lu·mis·ter·ol
| \ lü-ˈmis-tə-ˌrȯl
, -ˌrōl
\
, -ˌrōl
\
Medical Definition of lumisterol
: a crystalline compound stereoisomeric with ergosterol from which it is formed by ultraviolet irradiation as an intermediate product in the production of tachysterol and vitamin D2