Avernus

Latin Avernus, from Ancient Greek ἄορνος (áornos), ἄϝορνος (áwornos, “birdless”), from ἀ- (a-, “without”) + ὄρνις (órnis, “bird”). The lack of birds was likely due to fatal gases like carbon dioxide seeping from the volcanically active lake.

Avernus

1. The entrance to Hell or the underworld, or the underworld itself.
   • c. 1587–1588, [Christopher Marlowe], Tamburlaine the Great. […] The First Part […], 2nd edition, part 1, London: […] [R. Robinson for] Richard Iones, […], published 1592, →OCLC; reprinted as Tamburlaine the Great (A Scolar Press Facsimile), Menston, Yorkshire, London: Scolar Press, 1973, →ISBN, Act I, scene ii:

     His fiery eies are fixt vpon the earth.
     As if he now deuiſ’d some Stratageme:
     Or meant to pierce Auernus darkſome vauts.
     To pull the triple headed dog from hell.

2. A lake in Southern Italy.
   • 1807, [Germaine] de Staël Holstein, translated by D[ennis] Lawler, “[[Book XIII. Vesuvius and the plain of Naples.] Chap[ter] IV.] The extempore effusion of Corinna on the Plain of Naples.”, in Corinna; or, Italy. […], volume III, London: […] Corri, […]; and sold by Colburn, […], and Mackenzie, […], →OCLC, page 234:

     I perceive the Lake Avernus, an extinguished volcano, whose waves once inspired terror.

Ancient Greek ἄορνος (áornos), ἄϝορνος (áwornos, “birdless”), from ἀ- (a-, “without”) + ὄρνις (órnis, “bird”). The lack of birds was likely due to fatal gases like carbon dioxide seeping from the volcanically active lake.

View of the lake

Avernus m sg (genitive Avernī); second declension

1. Avernus (lake in Southern Italy)
2. The underworld

Second-declension noun, with locative, singular only.

• Avernālis

• “Avernus”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “Avernus”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• Avernus in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.