“Number discovered in the 1500s” crossword clue

Reveal the answer to see why it works and where this clue has appeared before.ETHER is the answer to the New York Times crossword clue “Number discovered in the 1500s”. It was last seen in the puzzle of October 24, 2025, where it runs at 53 Across and fills 5 squares. It crosses 5 other entries in that grid — those are listed below and are the quickest way to confirm the letters you already have.