The Collaborative International Dictionary of English v.0.48:

Nobility \No*bil"i*ty\, n. [L. nobilitas: cf. OF. nobilit['e].
   See Noble.]
   1. The quality or state of being noble; superiority of mind
      or of character; commanding excellence; eminence.
      [1913 Webster]

            Though she hated Amphialus, yet the nobility of her
            courage prevailed over it.            --Sir P.
                                                  Sidney.
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            They thought it great their sovereign to control,
            And named their pride nobility of soul. --Dryden.
      [1913 Webster]

   2. The state of being of high rank or noble birth; patrician
      dignity; antiquity of family; distinction by rank,
      station, or title, whether inherited or conferred.
      [1913 Webster]

            I fell on the same argument of preferring virtue to
            nobility of blood and titles, in the story of
            Sigismunda.                           --Dryden.
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   3. Those who are noble; the collective body of nobles or
      titled persons in a state; the aristocratic and patrician
      class; the peerage; as, the English nobility.
      [1913 Webster]

WordNet (r) 3.0 (2006):

nobility
    n 1: a privileged class holding hereditary titles [syn:
         nobility, aristocracy]
    2: the quality of elevation of mind and exaltation of character
       or ideals or conduct [syn: nobility, nobleness,
       magnanimousness, grandeur]
    3: the state of being of noble birth [syn: nobility,
       noblesse]