Wiktionary
n. A one-piece, horizontal tailplane, used especially on high-speed aircraft
Wikipedia
A stabilator, more frequently all-moving tail or all-flying tail, is a fully movable aircraft stabilizer. It serves the usual functions of longitudinal stability, control and stick force requirements otherwise performed by the separate fixed and movable parts of a conventional horizontal stabilizer. Apart from a higher efficiency at high Mach number, it is a useful device for changing the aircraft balance within wide limits, and for mastering the stick forces.
Stabilator (a portmanteau of "stabilizer-elevator") is also known in aircraft terminology as all moving tailplane, all-movable tail(plane), all-moving stabilizer, all flying tail(plane), full-flying stabilizer, flying tail and slab tailplane.
Usage examples of "stabilator".
Conforming to the latest stealth technology developed at the Anger Institute, its fuselage, wings, and low-profile V-shaped stabilators consisted of a series of gentle curves none of which reflected enough radar to be visible even on phased-array or lookdown radar systems.