Létal

Létal is a French adjective that describes something capable of causing death. In standard usage, it denotes the lethal potential or deadly nature of an agent, substance, weapon, or condition. The feminine form is létale and the plural forms are létaux (masc.) and létales (fem.). The term is often found in scientific, medical, safety, and regulatory writings, as well as in law and policy discussions concerning toxicity, risk assessment, and hazard classification.

Etymology and meaning: létal derives from Latin letālis, which relates to death. In French, létal is distinguished from other related terms like mortel and fatal. Mortel is a broader term for deadly or mortal in everyday language, while létal specifically emphasizes the capacity to cause death, rather than merely being harmful or dangerous.

Usage and context: Common phrases include arme létale (lethal weapon), substance létale or agent létal (lethal substance or lethal agent), and dose létale (lethal dose). In toxicology and pharmacology, létal is used to describe characteristics that lead to death, such as a substance’s létalité or a treatment’s létal threshold. The term is typically reserved for formal or technical contexts; everyday language may prefer mortel or fatal, depending on nuance.

Relation to other terms: Létal contrasts with sublétal (near-lethal), non létal (non-lethal), and avec létalité variable (with variable lethality). In safety standards, classifications often specify whether a hazard is létal to humans, animals, or environmental organisms.

See also: fatal, mortel, toxicité, dose létale, létalité, hazard.