Source : Webster's Revised Unabridged Dictionary (1913)

Illinition \Il`li*ni"tion\, n. [L. illinire, illinere, to
   besmear; pref. il- in, on + linire, linere, to smear.]
   1. A smearing or rubbing in or on; also, that which is
      smeared or rubbed on, as ointment or liniment.

   2. A thin crust of some extraneous substance formed on
      minerals. [R.]

            A thin crust or illinition of black manganese.
                                                  --Kirwan.