All defined terms are in italics and are listed alphabetically in the Definitions section - see pages 2235.
If the player deems his ball to be unplayable, he must, under penalty of one stroke:
Drop a ball behind the point where the ball lay, keeping that point directly between the hole and the spot on which the ball is dropped, with no limit to how far behind that point the ball may be dropped; or
Drop a ball within two club-lengths of the spot where the ball lay, but not nearer the hole.
When proceeding under this Rule, the player may lift and clean his ball or substitute a ball.
Match play - Loss of hole; Stroke play - Two strokes.