What does lethality mean?
Lethality is the quality or degree of being capable of causing death. It is used especially when discussing weapons, poisons, diseases, industrial hazards, and other dangers to life, and it can describe either a general dangerous quality or a measured degree of that quality. In medicine and toxicology, lethality may refer to the proportion of cases resulting in death; in military and security contexts, it often describes how effective a weapon or attack is at causing death. The word is more formal and technical than the everyday adjective deadly, making it especially appropriate for scientific, medical, legal, and strategic discussion. Although related to fatality, lethality focuses on the potential to cause death rather than the fact or rate of death itself.
nounThe quality or degree of being capable of causing death. In technical and professional contexts, it refers to the potential lethality of a weapon, substance, disease, or other hazard.
- The quality or degree of being capable of causing death.
"The researchers measured the lethality of the compound before advancing to clinical trials."
"The poison was tested for lethality and long-term effects."
"The report assessed the lethality of the missile system under realistic conditions."
The plural is grammatically possible but uncommon in normal use.
"The researchers compared the lethalities of several chemical agents."
Lethality measures a hazard's potential to kill, not the number of deaths it has actually caused.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does lethality come from?
Lethality was formed in English by adding the suffix -ity to the adjective lethal, which came through Latin from lethalis, meaning “causing death.” The Latin adjective is associated with lethum, “death,” whose deeper history is connected with Greek. The resulting noun has developed a largely technical use in the measurement and description of danger to life.
How lethality is actually used
Chiefly formal or technical, especially in military, medical, toxicological, biological, and safety contexts. It is less common in ordinary conversation, where people may say that something is deadly or fatal instead.
Easily confused with lethality
Lethality describes the capacity or potential to cause death, whereas mortality refers to the incidence or rate of death in a population.