Traditionally "PMO" should mean Project Management Office - what the role of the organization's PMO is variable. One military contractor I worked for had the PMO split into different "disciplines" with Business Operations PMs (poor dudes who just had to generate requirements from the Government), Implementation PMs and Software Dev PMs all in different areas.
Other organizations the PMO is the chief authority and acts as more or less as an consultant within that Organization to make sure practices, processes, frameworks and/or any other HR/Business buzzwords that they append to Project Management as a whole is followed - I've been in a small insurance company where the "PMO" had a Program Director and a bunch of other Business (not technical) people in it that directed the IT department in how they were supposed to lead projects and develop software.
And even rarer - I was in another MIL/GOV Contractor company that had a PMO mean Project Management Officer, he was essentially a Director or VP of Operations that tried to institute his Waterfall methodologies to our Scrum Teams.
So - examples aside, if it is a new department there will be some growing pains, especially as it continues to evolve and define itself.