poisoning: Death of the organism directly attributable to exposure to a toxic substance e.g., pesticide. Compare with Sub-lethal poisoning.

likely to cause or capable of causing the death of an organism. A lethal gene is one which could either cause an aborted fetus or the death of the organism at some later stage of its life.

An abnormality of genetic origin causing the death of the organism possessing it.

Causing death in a feotus or newborn.

Fatal or deadly.

Deadly, fatal, capable of causing death, death-dealing. The word "lethal" comes from the Latin "letum" meaning "death or destruction."