AMMONIA
Set to 4 different clues across 4 published puzzles, most often “It's lighter than air” — The New York Times, Sunday, 9 November 2008.
7 letters
Every clue on record, most used first
- It's lighter than aironce
The New York Times — Sunday, 9 November 2008
- Common cleanseronce
The New York Times — Wednesday, 1 August 2007
- Unbreathable part of an atmosphereonce
The New York Times — Friday, 2 September 2005
- Suffocating solutiononce
The New York Times — Saturday, 5 December 1998