transonic

IPA: trænsˈɑnɪk

Just below, or just above, the speed of sound (0.8 < Ma < 1.2 approximately).
Passing from subsonic to supersonic, or vice versa.
Travelling through a fluid (commonly air) at a speed where regions of supersonic and subsonic flow coexist simultaneously over different portions of the surface of the moving object in question.

Examples of "transonic" in Sentences

The aerodynamics between the tank and tower at transonic.
The LAS can only get on the order of hundreds of feet away from Ares during the transonic region.
The term "sound barrier" was coined for when an aircraft attempted to move from transonic to supersonic speed.
The 'transonic' stage of a 7mm Weatherby is at about 1400 yards, a 30-06 at about 1200 yards, and my old slowpoke .35 Whelen is at 700 yards.
Such design is very complicated since you fly through all possible flow regimes: From hypersonics down to supersonic, transonic and subsonic.
If bullets become unstable when they travel through the "transonic" stage, then why do 22 long rifle are still flying true even at 600 yards!!!
Bullets become unstable when they travel through the "transonic" stage (where the bullet goes from being supersonic to subsonic) the reason for this as best as I understand is due to the change in the way the air flows over the grooves in the bullet that the rifling engraves in its surface.