The amount of a radioactive material?that will undergo one decay (disintegration) per second. For more information, see "Primer on Radiation Measurement" at the end of this document
Centers for Disease Control and Prevention, Emergency Preparedness and Response, Radiation Emergencies, Radiation Dictionary, U.S. Department of Health and Human Services, Atlanta, GA, USA 2011. http://emergency.cdc.gov/radiation/glossary.asp, (Dzstr/ Rad Emr - Amer) {820}