Plain English Meaning
A type of FAA approval that says an airplane is built strong enough for aerobatic flying — loops, rolls, spins, and other extreme maneuvers — not just ordinary flight.
Full Definition
An FAA airworthiness category for airplanes certificated under 14 CFR Part 23 that are approved for maneuvers beyond those permitted in the normal or utility categories, including intentional spins and any flight maneuver the manufacturer demonstrates and the FAA approves during certification. Aircraft in this category are built to withstand higher load factors (typically +6.0g / -3.0g) than normal or airplanes.