Supersonic/ˌsuːpərˈsɑːnɪk/ Definition 1 of 2Pro Tip 1/3Speed Context Used to describe objects moving faster than sound, usually in aerospace and military contexts. The supersonic missile was launched during the test. Pro Tip 2/3Technical Term A technical term often found in science, engineering, and aviation. Supersonic aerodynamics are critical for a stealth fighter's design. Pro Tip 3/3Not Sonic Speed Despite 'sonic' in the name, it means faster than sound, not simply the speed of sound. Breaking the sound barrier means achieving supersonic speed.