n. [ Prov. E. alk; akin to Dan. alke, Icel. & Sw. alka. ] (Zool.) A name given to various species of arctic sea birds of the family Alcidæ. The great auk, now extinct, is Alca impennis (or Plautus impennis) . The razor-billed auk is Alca torda. See Puffin, Guillemot, and Murre. [ 1913 Webster ]