TOPIC: OPM versus PMO

What is the difference and/or relation between OPM (Organizational Project Management) and PMO (Project office Management)?

OPM is a method and alignment of business units for performing work using project management concepts. PMO is the body overseeing the business units that are running sponsored projects. The PMBOK goes into more detail about PMO.

Thanks Michael!
it's a little bit difficult for me, finding the exact limits between: PMO, OPM and Project Governance. Now a little bit more clear.
Thanks

I try to answer these questions in a way that it 'clicked' with me in my understanding of the topic:

The PMO owns and manages the processes defined within OPM.