Definition of Permo–Triassic
adjective
Geology relating to or denoting the boundary of the Permian and Triassic periods, about 245 million years ago. Mass extinctions occurred at this time, marking the end of the Palaeozoic era. (as noun
the Permo–Triassic or
Permo–Trias)
the Permian and Triassic periods together or the system of rocks deposited during them.
