Answer: machi

AnswerCrossword Clue
MACHIYeager's breakthrough
MACHISpeed of sound
MACHISpeed at the sound barrier.
MACHIA certain speed of sound.
MACHISpeed-of-sound term.
MACHIChuck Yeager's breakthrough
MACHIBarrier-breaking speed
MACHISpeed exceeded by SSTs
MACHIChuck Yeager goal?
machi(Hinglish) as in machi chips, fish and chips