\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.