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