(rare) Of, or related to extinction.

(astronomy) the dimming of light from the stars due to absorption and scattering from dust in the interstellar medium

plural of mass extinction

(evolutionary theory, geology) A sharp decrease in the total number of species in a relatively short period of time; specifically, a loss of ∼75% of all species on the planet over a geologically interval of less than 3 million years, as a result of a mass extinction event.

language death

(countable) A memory of a neutral or positive experience associated with a stimulus which was created after a negative experience and conditioned response toward that stimulus.

plural of extinct language

A dead language.

(biology, neologism) The process of returning an extinct species back into the world.

past tense of de-extinction