D defs.my
Entry 1 sense Webster, 1913

Residuum

/(-?m)/ · Re·sid·u·um · IPA /ɹɛˈzɪ.dju.ʌm/
01 n. That which is left after any process of separation or purification; that which remains after certain specified deductions are made; residue.
  1. 1.
    That which is left after any process of separation or purification; that which remains after certain specified deductions are made; residue.
    ““I think so,” is the whole residuum . . . after evaporating the prodigious pretensions of the zealot demagogue.” — L. Taylor.