ARCSIN
Set to 2 different clues across 2 published puzzles, most often “Inverse trig function” — The New York Times, Thursday, 18 December 2008.
6 letters
Every clue on record, most used first
- Inverse trig functiononce
The New York Times — Thursday, 18 December 2008
- It's measured in radiansonce
The New York Times — Saturday, 29 April 2006