| Answer | Crossword Clue |
|---|---|
| MACH | Speed-ratio number |
| MACH | -- number (speed ratio) |
| MACH | ... number (speed ratio) |
| MACH | Sound-speed ratio number |
| MACH | Number representing speed-sound ratio. |
| MACH | Speed ratio |
| MACH | Speed ratio. |
| MACH | Speed of sound ratio |
| MACH | Speed-of-sound ratio |
| MACH | Physicist for whom a speed-of-sound ratio is named |
