The Collaborative International Dictionary of English v.0.48:

commonality \com`mon*al"i*ty\ n.
   1. the sharing of common attributes.

   Syn: commonness.
        [WordNet 1.5]

   2. a characteristic held in common; a common feature.
      [PJC] commonalty

The Collaborative International Dictionary of English v.0.48:

commonalty \com"mon*al*ty\, commonality \com`mon*al"i*ty\, n.;
   pl. Commonalties. [OF. communalt['e]; F. communaut['e], fr.
   communal. See Communal.]
   1. The common people; those classes and conditions of people
      who are below the rank of nobility; the commons.
      [1913 Webster]

            The commonalty, like the nobility, are divided into
            several degrees.                      --Blackstone.
      [1913 Webster]

            The ancient fare of our kings differed from that of
            the commonalty in plenteousness only. --Landon.
      [1913 Webster]

   2. The majority or bulk of mankind. [Obs.] --Hooker.
      [1913 Webster]

WordNet (r) 3.0 (2006):

commonality
    n 1: a class composed of persons lacking clerical or noble rank
         [syn: commonalty, commonality, commons]
    2: sharing of common attributes [syn: commonality,
       commonness] [ant: individualism, individuality,
       individuation]