(ˈ)tran|sänik, -raan-, -nēk adjective
also trans-son·ic -nz|s-, -n(t)s|s-
Etymology: trans- + -sonic (as in supersonic ); from the fact that such speeds are transitional between subsonic and supersonic speeds
1. : of, being, or relating to a speed approximating the speed of sound in air : relating to a speed in air of about 1087 feet per second or about 741 miles per hour at sea level — often used of aeronautical speeds between 600 and 900 miles per hour; compare sonic , subsonic , supersonic
2. : moving, capable of moving, or utilizing air currents moving at a transonic speed