What is...

FBO – Fixed Based operator.
The FBO is an aircraft service center at an airport that typically provides a host of services including fuels, lubricants, de-icing fluids, hydraulic fluids, maintenance, aircraft hangar services, and ground handling support.
The FBO is quite similar, so-to-speak, to a highway stop-by! One best suited to the weary traveler!
Besides the basic services mentioned above, FBO’s also provide weather and communication facilities, including internet access for customers. Now, you’re looking at travelers, so the next thing would be food! So, there would ideally be vending machines and refrigerators stocked with snacks.
Additionally some FBO’s may also provide car rental services, hotel reservations and lounge facilities, for example, to the overnight travelers.
Some of the amenities and conveniences that could also be provided by an FBO include:
Special Flight planning rooms equipped with updated maps, access to weather services;
Executive conferencing areas;
Private showers/restrooms;
Catering and ground transportation for crews;
Free hi-speed internet connections.

So, an FBO is quite the “customer centric” aircraft service center, and though they do provide extensive maintenance support, the focus is on the “overall customer experience” at the airport, a bit different from the MRO focus on total maintenance support.