the basic unit in the SI system that is used to measure the amount of biological damage caused by various types of ionizing radiation, equal to the dose that produces the same amount of damage in human tissue as one gray of X-rays (100 rem or 8.38 roentgens): abbrev. Sv
Abbr. Sv A unit of ionizing radiation absorbed dose equivalent in the International System of Units, obtained as a product of the absorbed dose measure in grays and a dimensionless factor, stipulated by the International Commission on Radiological Protection, and indicating the biological effectiveness of the radiation.
The SI derived unit used to measure the amount of radiation necessary to produce the same effect on living tissue as one gray of high-penetration x-rays. The sievert is named after Swedish physicist Rolf Sievert (1896-1966).