Source : Webster's Revised Unabridged Dictionary (1913)

Oleograph \O`le*o*graph\, n. [L. oleum oil + -graph.]
   1. (Chem.) The form or figure assumed by a drop of oil when
      placed upon water or some other liquid with which it does
      not mix.

   2. (Painting) A picture produced in oils by a process
      analogous to that of lithographic printing.