ATTO
Set to 2 different clues across 7 published puzzles, most often “Quintillionth: Prefix” — The New York Times, Sunday, 15 February 2009.
4 letters
Every clue on record, most used first
- Quintillionth: Prefix5 times
The New York Times — Sunday, 15 February 2009
- One-quintillionth: Prefix2 times
The New York Times — Saturday, 27 August 2005