Source : Webster's Revised Unabridged Dictionary (1913)

Oleo oil \O`le*o oil\
   An oil expressed from certain animal fats (esp. beef suet),
   the greater portion of the solid fat, or stearin, being left
   behind. It is mixture of olein, palmitin, and a little
   stearin.

Source : WordNet®

oleo oil
     n : obtained from beef fat; used in making margarine and soap
         and in lubrication