The Collaborative International Dictionary of English v.0.48:

Ursa \Ur"sa\, n. [L. ursa a she-bear, also, a constellation,
   fem. of ursus a bear. Cf. Arctic.] (Astron.)
   Either one of the Bears. See the Phrases below.
   [1913 Webster]

   Ursa Major [L.], the Great Bear, one of the most
      conspicuous of the northern constellations. It is situated
      near the pole, and contains the stars which form the
      Dipper, or Charles's Wain, two of which are the Pointers,
      or stars which point towards the North Star.

   Ursa Minor [L.], the Little Bear, the constellation nearest
      the north pole. It contains the north star, or polestar,
      which is situated in the extremity of the tail.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Bear \Bear\ (b[^a]r), n. [OE. bere, AS. bera; akin to D. beer,
   OHG. bero, pero, G. b[aum]r, Icel. & Sw. bj["o]rn, and
   possibly to L. fera wild beast, Gr. fh`r beast, Skr. bhalla
   bear.]
   [1913 Webster]
   1. (Zool.) Any species of the genus Ursus, and of the
      closely allied genera. Bears are plantigrade Carnivora,
      but they live largely on fruit and insects.
      [1913 Webster]

   Note: The European brown bear (Ursus arctos), the white
         polar bear (Ursus maritimus), the grizzly bear
         (Ursus horribilis), the American black bear, and its
         variety the cinnamon bear (Ursus Americanus), the
         Syrian bear (Ursus Syriacus), and the sloth bear, are
         among the notable species.
         [1913 Webster]

   2. (Zool.) An animal which has some resemblance to a bear in
      form or habits, but no real affinity; as, the woolly bear;
      ant bear; water bear; sea bear.
      [1913 Webster]

   3. (Astron.) One of two constellations in the northern
      hemisphere, called respectively the Great Bear and the
      Lesser Bear, or Ursa Major and Ursa Minor.
      [1913 Webster]

   4. Metaphorically: A brutal, coarse, or morose person.
      [1913 Webster]

   5. (Stock Exchange) A person who sells stocks or securities
      for future delivery in expectation of a fall in the
      market.
      [1913 Webster]

   Note: The bears and bulls of the Stock Exchange, whose
         interest it is, the one to depress, and the other to
         raise, stocks, are said to be so called in allusion to
         the bear's habit of pulling down, and the bull's of
         tossing up.
         [1913 Webster]

   6. (Mach.) A portable punching machine.
      [1913 Webster]

   7. (Naut.) A block covered with coarse matting; -- used to
      scour the deck.
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   Australian bear. (Zool.) See Koala.

   Bear baiting, the sport of baiting bears with dogs.

   Bear caterpillar (Zool.), the hairy larva of a moth, esp.
      of the genus Euprepia.

   Bear garden.
      (a) A place where bears are kept for diversion or
          fighting.
      (b) Any place where riotous conduct is common or
          permitted. --M. Arnold.

   Bear leader, one who leads about a performing bear for
      money; hence, a facetious term for one who takes charge of
      a young man on his travels.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Ursa Major
    n 1: a constellation outside the zodiac that rotates around the
         North Star [syn: Great Bear, Ursa Major]