The term Sievert is the unit term of one dose equivalent. The dose equivalent measures the biological radiation exposure, i. e. it is a unit derived from radiation protection. It is defined as
Dose equivalent = energy dose x quality factor
One Sievert equals one Joule divided by one kilogramme: 1Sv = 1J/1kg
If the dose equivalent is related to a certain period of time, it is called dose rate:
For example: 1 Sv/h - one Sievert per hour or 2 mSv/h - two milli-Sievert per hour.