### - o -

- object : IPerformanceMetric
- objectSize : IFsObjInfo
- offset : IFile
- online : ISnapshot
- openMode : IFile
- operatingSystem : IHost
- operation : IProgress
- operationCount : IProgress
- operationDescription : IProgress
- operationPercent : IProgress
- operationWeight : IProgress
- originX : IGuestMonitorChangedEvent
- originY : IGuestMonitorChangedEvent
- OSName : IMachineDebugger
- OSTypeId : IMachine , IGuest
- OSVersion : IMachineDebugger , IHost
- overlay : IFramebuffer