[su.per.son.ic] adj [L super- + sonus sound--more at sound] (1919) 1: ultrasonic
2: of, being, or relating to speeds from one to five times the speed of sound in air--compare sonic
3: moving, capable of moving, or utilizing air currents moving at supersonic speed
4: relating to supersonic airplanes or missiles "the ~ age" -- su.per.son.i.cal.ly adv
[2]supersonic n (ca. 1924) 1: a supersonic wave or frequency
2: a supersonic airplane