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):

commonalty
    n 1: a class composed of persons lacking clerical or noble rank
         [syn: commonalty, commonality, commons]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

COMMONALTY, Eng. law. This word signifies, 1st. the common people of
England, as contradistinguished from the king and the nobles; 2d. the body
of a society as the masters, wardens, and commonalty of such a society.