Plain English Meaning
Airplanes powered by jet engines, which create forward push by sucking in air, burning fuel with it, and blasting the hot gases out the back.
Full Definition
Airplanes powered by jet engines that produce thrust by drawing in air, compressing it, mixing it with fuel and igniting it, then expelling the hot exhaust gases rearward at high velocity. This category includes pure turbojets and, in common FAA usage, turbofan-powered transport-category aircraft, which share similar handling characteristics, high-altitude performance, and operating procedures distinct from piston or turboprop airplanes.