Clues for the word "STOS"

We've had 2 crossword clues used for this word, and seen it 2 times in crosswords. It was last seen in Chronicle of Higher Education crossword on October 19, 2012.

Referring Clues

Things on rings
Playing pieces in the game of Go

Last Seen In

Chronicle of Higher Education - October 19, 2012
New York Times - June 11, 1998