|a loud explosive sound caused by the shock wave of an aircraft, etc, travelling at supersonic speed|
|a gadget; dingus; thingumbob.|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
A shock wave of compressed air caused by an aircraft traveling faster than the speed of sound. It is often audible as a loud, explosive sound, and it sometimes causes damage to structures on the ground.
See boom, sonic.