on c - orga
- open nose body
- open pier
- open pit type ammunition shelter
- open point bullet
- open position
- open railway car
- open relay
- open route
- open sided container
- open star cluster
- open storage area
- open system
- open traverse
- opened silo
- opening
- opening charge
- opening cut
- opening of spring
- opening of the valve
- opening process
- opening roof
- opening shock load
- opening time
- operability
- operated circuit
- operating accident
- operating ambient
- operating and pipeline construction foreman
- operating characteristic
- operating control
- operating costs
- operating division
- operating economy
- operating fluid
- operating lever
- operating lever latch knob
- operating lever pin
- operating lever spindle
- operating lug
- operating maintenance
