hypersonic

hyper- +‎ sonic. Doublet of supersonic.

hypersonic (comparative more hypersonic, superlative most hypersonic)

1. (of a speed, aviation) Equal to, or greater than, or capable of achieving, five times the speed of sound.
   • 2021 June 3, Julian E. Barnes, Helene Cooper, “U.S. Finds No Evidence of Alien Technology in Flying Objects, but Can’t Rule It Out, Either”, in The New York Times‎, →ISSN:

     He said there was worry among intelligence and military officials that China or Russia could be experimenting with hypersonic technology.

2. (of a speed, aeronautics) Far enough above the speed of sound as to cause significant differences in behaviour due to chemical reactions or dissociation of the air.

• Honeycrisp