“Supersonic speed number” crossword clue

Reveal the answer to see why it works and where this clue has appeared before.MACH is the answer to the New York Times crossword clue “Supersonic speed number”. It was last seen in the puzzle of January 6, 2025, where it runs at 1 Across and fills 4 squares. It crosses 4 other entries in that grid — those are listed below and are the quickest way to confirm the letters you already have.