The Collaborative International Dictionary of English v.0.48:

Surplusage \Sur"plus*age\, n. [See Surplus, and cf.
   Superplusage.]
   1. Surplus; excess; overplus; as, surplusage of grain or
      goods beyond what is wanted.
      [1913 Webster]

            Take what thou please of all this surplusage.
                                                  --Spenser.
      [1913 Webster]

            A surplusage given to one part is paid out of a
            reduction from another part of the same creature.
                                                  --Emerson.
      [1913 Webster]

   2. (Law) Matter in pleading which is not necessary or
      relevant to the case, and which may be rejected.
      [1913 Webster]

   3. (Accounts) A greater disbursement than the charge of the
      accountant amounts to. [Obs.] --Rees.
      [1913 Webster]

WordNet (r) 3.0 (2006):

surplusage
    n 1: a quantity much larger than is needed [syn: excess,
         surplus, surplusage, nimiety]