Avernal


Also found in: Wikipedia.

A·ver·no

 (ä-vĕr′nō) Ancient name A·ver·nus (ə-vûr′nəs)
A small crater lake of southern Italy near the Tyrrhenian Sea west of Naples. Because of its gloomy aspect and intense sulfuric vapors, now extinguished, the ancient Romans regarded it as the entrance to the underworld.

A·ver′nal adj.