The Collaborative International Dictionary
Plautus impennis
Auk \Auk\, n. [Prov. E. alk; akin to Dan. alke, Icel. & Sw. alka.] (Zo["o]l.) A name given to various species of arctic sea birds of the family Alcid[ae]. The great auk, now extinct, is Alca impennis (or Plautus impennis) . The razor-billed auk is Alca torda. See Puffin, Guillemot, and Murre.