Oldu - over
- Oldum coupling
- olein
- oleo gear
- oleo-pneumatic riveter with steel sleeve and safety flap for expulsion of the spent nails
- oleo-pneumatic shock absorber
- oleo-shock absorption
- oleodynamic device
- oleometer
- olericulture
- olive
- olive and nut
- olive coupling
- olive coupling for steel
- omnibus
- omnidirectional
- ompound stationary obstructions
- on
- on approval
- on corner
- on down grade
