Related Clues:
- First of six popes
- Speed measure
- Supersonic unit
- Sainted eighth-century pope
- Eighth century pope
- Big name in ballistics
- ___ 5 ('Speed Racer' car)
- St. ___ Girl (beer with busty spokesmodels)
- Yeager's speed
- Type of radar
- Supersonic reading
- St. ___ Girl (beer brand)
- Physics Nobelist Wolfgang
- Pope after Stephen II
- Speed-of-sound ratio