An organisational structure that supports project, programme or portfolio work, ranging from an advisory office to one that runs the projects itself.
A PMO is defined by two independent settings, and naming only one of them is where most confusion about the term comes from. The first is authority: a supportive office advises and can be ignored, a controlling office makes compliance a condition of proceeding, and a directive office supplies the project managers and runs the work itself. The second is level, meaning the scope it serves, from a single project up through a programme, a division and the whole enterprise. The two vary freely, so an enterprise office can hold no real power and a single project office can hold a great deal. The practical test of which type you have is what happens on the day a project ignores it.
See also
The named group holding authority to approve or reject a change request, and the only body that can move an approved change into the baseline.
The transfer of a delivered output to the people who will run it, understood as a transition period rather than a single date.
Where this comes up
Predictive work gets an ending for free, the day the thing is handed over. Iterative work has to manufacture one, which is why so much of it never formally ends at all.
Three types, separated by one variable: how much authority the office holds. Supportive advises, controlling requires, directive runs the work. Level is a second axis and a different question.