Wiktionary
k-t extinction event
alt. The rapid dying off of a large percentage of all animal species in a comparatively short period of time 65.5 million years ago. This coincides with the end of the Cretaceous period, and may have been caused by an impact event. n. The rapid dying off of a large percentage of all animal species in a comparatively short period of time 65.5 million years ago. This coincides with the end of the Cretaceous period, and may have been caused by an impact event.