one- - over
- opener
- openhearth steel
- opening
- opening for evacuation
- opening of break
- opening of taphole
- opening-up
- openside feeder
- opentop feeder
- operate
- operating characteristic curve
- operating characteristic curve of sampling plan
- operating characteristics of the tube
- operating conditions
- operating crew
- operating density
- operating effervescive
- operating facilities
- operating flexibility
- operating floor
- operating fluid
- operating house
- operating line
- operating margin
- operating mechanism
- operating motor
- operating of blast furnace
- operating period
- operating platform
- operating principles
- operating profile
- operating pulpit
- operating region
- operating schedule
- operating speed
- operating temperature
- operating threshold
- operating time
- operation
- operation analysis