The Collaborative International Dictionary of English v.0.48:

Electorate \E*lect"or*ate\, n. [Cf. F. ['e]lectorat.]
   1. The territory, jurisdiction, or dignity of an elector, as
      in the old German empire.
      [1913 Webster]

   2. The whole body of persons in a nation or state who are
      entitled to vote in an election, or any distinct class or
      division of them.
      [1913 Webster]

            The middle-class electorate of Great Britain. --M.
                                                  Arnold.
      [1913 Webster]

WordNet (r) 3.0 (2006):

electorate
    n 1: the body of enfranchised citizens; those qualified to vote

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "electorate":
   Kreis, archbishopric, archdiocese, arrondissement, bailiwick,
   bishopric, borough, canton, chooser, city, commune,
   congressional district, constablewick, constituency, constituents,
   county, departement, diocese, district, duchy, elector,
   electoral college, electoral district, electors, government,
   hamlet, hundred, magistracy, metropolis, metropolitan area, oblast,
   okrug, optant, parish, precinct, principality, province, region,
   riding, selector, sheriffalty, sheriffwick, shire, shrievalty,
   soke, stake, state, territory, town, township, village, voter,
   wapentake, ward