- opera-house
- operability
- operable
- operable time
- operable walls
- operand
- operand field
- operant
- operate
- operate current
- operate lag
- operate mode
- operate relay
- operate time
- operate voltage
- operated
- operatic
- operating
- operating accident
- operating account
- operating agreement
- operating altitude
- operating angle
- operating asset
- operating assets
- operating bridge
- operating budget
- operating capacity
- operating capital
- operating card
- operating ceiling
- operating characteristic
- operating company
- operating condition
- operating conditions
- operating console
- operating control
- operating convenience
- operating cost
- operating costs
- operating crank
- operating current
- operating cycle
- operating deficit
- operating delay
- operating diskette
- operating duration
- operating duty
- operating effectiveness
- operating efficiency
- operating engineer
- operating environment
- operating error
- operating expense
- operating expenses
- operating face
- operating fault
- operating feature
- operating floor
- operating frequency
- operating fund
- operating gate
- operating height
- operating hour
- operating instruction
- operating instructions
- operating investigation
- operating key
- operating lease
- operating ledger
- operating level
- operating lever
- operating lifetime
- operating line
- operating loss
- operating maintenance
- operating management
- operating margin
- operating mechanism
- operating microscope
- operating mode
- operating order
- operating parameter
- operating part
- operating period
- operating permit
- operating personnel
- operating piston
- operating plan
- operating platform
- operating point
- operating pole
- operating position
- operating potential
- operating power
- operating pressure
- operating principle
- operating provision
- operating pump
- operating range