Definition of "oleo"

(aviation) A type of energy-absorbing landing gear strut in which sudden compression or extension of the strut causes a gas-filled chamber to push or pull a piston which forces oil through a small orifice, resulting in absorption of energy through viscous effects.  examples

(US) The various fats and oils that go into the making of margarine.  examples

(US, dated) Margarine.  examples