“Letter symbolizing the ratio of a circle's circumference to its radius” crossword clue

Reveal the answer to see why it works and where this clue has appeared before.TAU is the answer to the New York Times crossword clue “Letter symbolizing the ratio of a circle's circumference to its radius”. It was last seen in the puzzle of February 1, 2026, where it runs at 72 Across and fills 3 squares. It crosses 3 other entries in that grid — those are listed below and are the quickest way to confirm the letters you already have.