Fatality rate is the number of deaths out of a total number of cases of a particular disease or situation, usually expressed as a percentage. There are several synonyms that can be used interchangeably with the term fatality rate. These include mortality rate, death rate, lethal rate, and decease percentage. All of these synonyms refer to the same concept of measuring the number of deaths in a specific population over a given period. The term fatality rate is commonly used in epidemiology, public health, and medicine to track the severity of an outbreak or pandemic and to inform public policy decisions regarding disease control measures.