the.com/mass extinction

means A relatively sudden, planet-wide die-off wiping out a large share of species across many different groups at once, after which survivors radiate into the empty niches.

from 'Extinction' traces to Latin exstinguere, 'to put out, extinguish' (like snuffing a flame), later applied to species that are snuffed out of existence. 'Mass' comes from Latin massa, 'lump, dough, kneaded mass.' The phrase itself is modern scientific vocabulary — paleontologists and geologists in the 20th century, studying the fossil record's sharp die-off horizons (like the one marking the end of the dinosaurs), needed a term for extinction happening not species-by-species but in sudden, sweeping waves. The 'Big Five' mass extinctions became the field's organizing story only once radiometric dating and fossil surveys let scientists see those die-offs as simultaneous rather than scattered.