The Collaborative International Dictionary of English v.0.48:

elk \elk\ ([e^]lk), n. [Icel. elgr; akin to Sw. elg, AS. eolh,
   OHG. elaho, MHG. elch, cf. L. alces; perh. akin to E. eland.]
   (Zo["o]l.)
   A large deer, of several species. The European elk Alces
   alces (formerly Alces machlis or Cervus alces) is
   closely allied to the American moose. The American elk, or
   wapiti (Cervus Canadensis) the largest member of the deer
   family, has large, spreading antlers and is closely related
   to the European stag. See Moose, and Wapiti.
   [1913 Webster +PJC]

   Irish elk (Paleon.), a large, extinct, Quaternary deer
      (Cervus giganteus) with widely spreading antlers. Its
      remains have been found beneath the peat of swamps in
      Ireland and England. See Illustration in Appendix; also
      Illustration of Antler.

   Cape elk (Zo["o]l.), the eland. elk