In Tombstone, golfers begin their rounds with an allotment of strokes and they play until their strokes run out. The golfer who makes it farthest around the course is the winner.
The name comes from the fact that each golfer carries with him a flag, a small clipboard or other item to be staked in the ground at the point of their final stroke. The "tombstone," in this case, is the object placed in the ground where the golfer's round meets its end.
For more explanation of Tombstone, a k a Flags, see our entry for Flags.

