residuum

from WordNet (r) 3.0 (2006)

residuum
    n 1: something left after other parts have been taken away;
         "there was no remainder"; "he threw away the rest"; "he
         took what he wanted and I got the balance" [syn:
         {remainder}, {balance}, {residual}, {residue}, {residuum},
         {rest}]

from The Collaborative International Dictionary of English v.0.48

Residuum \Re*sid"u*um\ (-?m), n. [L. See {Residue}.]
   That which is left after any process of separation or
   purification; that which remains after certain specified
   deductions are made; residue.
   [1913 Webster]

         "I think so," is the whole residuum . . . after
         evaporating the prodigious pretensions of the zealot
         demagogue.                               --L. Taylor.
   [1913 Webster]