Inflected forms: pl. fa·tal·i·ties 1a. A death resulting from an accident or a disaster: highway fatalities.b. One that is killed as a result of such an occurrence: The driver was one of the fatalities.2. The ability to cause death or disaster. 3. The quality of being determined by fate. 4. A decree made by fate; destiny. 5. The quality of being doomed to disaster.