The Collaborative International Dictionary of English v.0.48:

Dipper \Dip"per\, n.
   1. One who, or that which, dips; especially, a vessel used to
      dip water or other liquid; a ladle.
      [1913 Webster]

   2. (Zool.)
      (a) A small grebe; the dabchick.
      (b) The buffel duck.
      (c) The water ouzel (Cinolus aquaticus) of Europe.
      (d) The American dipper or ouzel (Cinclus Mexicanus).
          [1913 Webster]

   The Dipper (Astron.), the seven principal stars in the
      constellation of the Great Bear; popularly so called from
      their arrangement in the form of a dipper; -- called also
      Charles's Wain. See Ursa Major, under Ursa.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dipper
    n 1: a ladle that has a cup with a long handle
    2: a cluster of seven stars in Ursa Minor; at the end of the
       dipper's handle is Polaris [syn: Little Dipper, Dipper]
    3: a group of seven bright stars in the constellation Ursa Major
       [syn: Big Dipper, Dipper, Plough, Charles's Wain,
       Wain, Wagon]
    4: small North American diving duck; males have bushy head
       plumage [syn: bufflehead, butterball, dipper,
       Bucephela albeola]
    5: small stocky diving bird without webbed feet; frequents fast-
       flowing streams and feeds along the bottom [syn: water
       ouzel, dipper]