Mexican standoff

Short definition from Wiktionary

Noun

1. 1
   A stalemate, or a confrontation among two or more sides that no side can win.
2. 2
   A stalemate, or a confrontation among two or more sides that no side can win: An inconclusive standoff, ending in mutual retreat.
3. 3
   A stalemate, or a confrontation among two or more sides that no side can win: A confrontation among two or more armed parties, none of which wants to attack first (fearing that the other could retaliate), but neither of which will disarm (for fear the other will attack).
4. 4
   A stalemate, or a confrontation among two or more sides that no side can win: A three-way or more standoff.
5. 5
   A stalemate, or a confrontation among two or more sides that no side can win: A pot that is split among the players because of a tie.
6. 6
   A near-collision between two trains; an averted cornfield meet.