The scene of a decisive conflict on a great scale.
Any great and crucial conflict.
An armageddon round, usually played when a match would otherwise end in a draw, where black wins drawn games and white is given more time as compensation.
A disaster, especially one which is large in scale and readily seen by public observers.
The aftermath of a train crash.
Someone (especially a woman) who is unbalanced and considered a mess, a disaster, one who is suffering personal ruin.
To ruin utterly and catastrophically, to cause to end in disaster.