The Collaborative International Dictionary of English v.0.48:

Bald eagle \Bald" ea"gle\ (Zool.)
   The white-headed eagle (Hali[ae]etus leucocephalus) of
   America. The young, until several years old, lack the white
   feathers on the head.
   [1913 Webster]

   Note: The bald eagle is represented in the coat of arms, and
         on the coins, of the United States.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Eagle \Ea"gle\, n. [OE. egle, F. aigle, fr. L. aquila; prob.
   named from its color, fr. aquilus dark-colored, brown; cf.
   Lith. aklas blind. Cf. Aquiline.]
   1. (Zo["o]l.) Any large, rapacious bird of the Falcon family,
      esp. of the genera Aquila and Hali[ae]etus. The eagle
      is remarkable for strength, size, graceful figure,
      keenness of vision, and extraordinary flight. The most
      noted species are the golden eagle (Aquila
      chrysa["e]tus); the imperial eagle of Europe (Aquila
      mogilnik or Aquila imperialis); the American bald eagle
      (Hali[ae]etus leucocephalus); the European sea eagle
      (Hali[ae]etus albicilla); and the great harpy eagle
      (Thrasaetus harpyia). The figure of the eagle, as the
      king of birds, is commonly used as an heraldic emblem, and
      also for standards and emblematic devices. See Bald
      eagle, Harpy, and Golden eagle.
      [1913 Webster]

   2. A gold coin of the United States, of the value of ten
      dollars.
      [1913 Webster]

   3. (Astron.) A northern constellation, containing Altair, a
      star of the first magnitude. See Aquila.
      [1913 Webster]

   4. The figure of an eagle borne as an emblem on the standard
      of the ancient Romans, or so used upon the seal or
      standard of any people.
      [1913 Webster]

            Though the Roman eagle shadow thee.   --Tennyson.
      [1913 Webster]

   Note: Some modern nations, as the United States, and France
         under the Bonapartes, have adopted the eagle as their
         national emblem. Russia, Austria, and Prussia have for
         an emblem a double-headed eagle.
         [1913 Webster]

   Bald eagle. See Bald eagle.

   Bold eagle. See under Bold.

   Double eagle, a gold coin of the United States worth twenty
      dollars.

   Eagle hawk (Zo["o]l.), a large, crested, South American
      hawk of the genus Morphnus.

   Eagle owl (Zo["o]l.), any large owl of the genus Bubo,
      and allied genera; as the American great horned owl (Bubo
      Virginianus), and the allied European species (B.
      maximus). See Horned owl.

   Eagle ray (Zo["o]l.), any large species of ray of the genus
      Myliobatis (esp. M. aquila).

   Eagle vulture (Zo["o]l.), a large West African bid
      (Gypohierax Angolensis), intermediate, in several
      respects, between the eagles and vultures.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Haliaeetus leucocephalus
    n 1: a large eagle of North America that has a white head and
         dark wings and body [syn: bald eagle, American eagle,
         Haliaeetus leucocephalus]