The Definitions are listed alphabetically and, in the Rules themselves, defined terms are in italics.
See "Move or Moved."
See "Lost Ball."
A ball is "in play" as soon as the player has made a stroke on the teeing ground. It remains in play until it is holed, except when it is lost, out of bounds or lifted, or another ball has been substituted, whether or not the substitution is permitted; a ball so substituted becomes the ball in play.
If a ball is played from outside the teeing ground when the player is starting play of a hole, or when attempting to correct this mistake, the ball is not in play and Rule 11-4 or 11-5 applies. Otherwise, ball in play includes a ball played from outside the teeing ground when the player elects or is required to play his next stroke from the teeing ground.
Exception in match play: Ball in play includes a ball played by the player from outside the teeing ground when starting play of a hole if the opponent does not require the stroke to be canceled in accordance with Rule 11-4a.
Grass-covered ground bordering or within a bunker, including a stacked turf face (whether grass-covered or earthen), is not part of the bunker. A wall or lip of the bunker not covered with grass is part of the bunker. The margin of a bunker extends vertically downwards, but not upwards.
A "burrowing animal" is an animal (other than a worm, insect or the like) that makes a hole for habitation or shelter, such as a rabbit, mole, groundhog, gopher or salamander.
When one caddie is employed by more than one player, he is always deemed to be the caddie of the player sharing the caddie whose ball (or whose partner's ball) is involved, and equipment carried by him is deemed to be that player's equipment, except when the caddie acts upon specific directions of another player (or the partner of another player) sharing the caddie, in which case he is considered to be that other player's caddie.
"Casual water" is any temporary accumulation of water on the course that is not in a water hazard and is visible before or after the player takes his stance. Snow and natural ice, other than frost, are either casual water or loose impediments, at the option of the player. Manufactured ice is an obstruction. Dew and frost are not casual water.
Note 1: A ball played at the hole being played is equipment when it has been lifted and not put back into play.
If a shared golf cart is being moved by one of the players sharing it (or his partner or either of their caddies), the cart and everything in it are deemed to be that player's equipment. Otherwise, the cart and everything in it are deemed to be the equipment of the player sharing the cart whose ball (or whose partner's ball) is involved.
Other shared equipment is deemed to be the equipment of the player who last used, wore, held or carried it. It remains that player's equipment until it is used, worn, held or carried by the other player (or his partner or either of their caddies).
The "flagstick" is a movable straight indicator, with or without bunting or other material attached, centered in the hole to show its position. It must be circular in cross-section. Padding or shock absorbent material that might unduly influence the movement of the ball is prohibited.
Single: A match in which one player plays against another player.
Threesome: A match in which one player plays against two other players, and each side plays one ball.
Foursome: A match in which two players play against two other players, and each side plays one ball.
Three-Ball: Three players play a match against one another, each playing his own ball. Each player is playing two distinct matches.
Best-Ball: A match in which one player plays against the better ball of two other players or the best ball of three other players.
Four-Ball: A match in which two players play their better ball against the better ball of two other players.
Individual: A competition in which each competitor plays as an individual.
Four-Ball: A competition in which two competitors play as partners, each playing his own ball. The lower score of the partners is the score for the hole. If one partner fails to complete the play of a hole, there is no penalty.
Note: For bogey, par and Stableford competitions, see Rule 32-1.
"Ground under repair" is any part of the course so marked by order of the Committee or so declared by its authorized representative. All ground and any grass, bush, tree or other growing thing within the ground under repair are part of the ground under repair. Ground under repair includes material piled for removal and a hole made by a greenkeeper, even if not so marked. Grass cuttings and other material left on the course that have been abandoned and are not intended to be removed are not ground under repair unless so marked.
When the margin of ground under repair is defined by stakes, the stakes are inside the ground under repair, and the margin of the ground under repair is defined by the nearest outside points of the stakes at ground level. When both stakes and lines are used to indicate ground under repair, the stakes identify the ground under repair and the lines define the margin of the ground under repair. When the margin of ground under repair is defined by a line on the ground, the line itself is in the ground under repair. The margin of ground under repair extends vertically downwards but not upwards.
Note: The Committee may make a Local Rule prohibiting play from ground under repair or an environmentally-sensitive area defined as ground under repair.
The "hole" must be 4 1⁄4 inches (108 mm) in diameter and at least 4 inches (101.6 mm) deep. If a lining is used, it must be sunk at least 1 inch (25.4 mm) below the putting green surface, unless the nature of the soil makes it impracticable to do so; its outer diameter must not exceed 4 1⁄4 inches (108 mm).
A "lateral water hazard" is a water hazard or that part of a water hazard so situated that it is not possible, or is deemed by the Committee to be impracticable, to drop a ball behind the water hazard in accordance with Rule 26-Ib. All ground and water within the margin of a lateral water hazard are part of the lateral water hazard.
When the margin of a lateral water hazard is defined by stakes, the stakes are inside the lateral water hazard, and the margin of the hazard is defined by the nearest outside points of the stakes at ground level. When both stakes and lines are used to indicate a lateral water hazard, the stakes identify the hazard and the lines define the hazard margin. When the margin of a lateral water hazard is defined by a line on the ground, the line itself is in the lateral water hazard. The margin of a lateral water hazard extends vertically upwards and downwards.
The "line of play" is the direction that the player wishes his ball to take after a stroke, plus a reasonable distance on either side of the intended direction. The line of play extends vertically upwards from the ground, but does not extend beyond the hole.
The "line of putt" is the line that the player wishes his ball to take after a stroke on the putting green. Except with respect to Rule 16-1e, the line of putt includes a reasonable distance on either side of the intended line. The line of putt does not extend beyond the hole.
"Loose impediments" are natural objects, including:
provided they are not:
Dew and frost are not loose impediments.
A ball is deemed "lost" if:
The player has put another ball into play because it is known or virtually certain that the ball, which has not been found, has been moved by an outside agency (see Rule 18-1), is in an obstruction (see Rule 24-3), is in an abnormal ground condition (see Rule 25-1c) or is in a water hazard (see Rule 26-1b or c); or
Time spent in playing a wrong ball is not counted in the five-minute period allowed for search.
A ball is deemed to have "moved" if it leaves its position and comes to rest in any other place.
The "nearest point of relief" is the reference point for taking relief without penalty from interference by an immovable obstruction (Rule 24-2), an abnormal ground condition (Rule 25-1) or a wrong putting green (Rule 25-3).
It is the point on the course nearest to where the ball lies:
that is not nearer the hole, and
where, if the ball were so positioned, no interference by the condition from which relief is sought would exist for the stroke the player would have made from the original position if the condition were not there.
Note: In order to determine the nearest point of relief accurately, the player should use the club with which he would have made his next stroke if the condition were not there to simulate the address position, direction of play and swing for such a stroke.
An "observer" is one who is appointed by the Committee to assist a referee to decide questions of fact and to report to him any breach of a Rule. An observer should not attend the flagstick, stand at or mark the position of the hole, or lift the ball or mark its position.
An "obstruction" is anything artificial, including the artificial surfaces and sides of roads and paths and manufactured ice, except:
Objects defining out of bounds, such as walls, fences, stakes and railings;
Any part of an immovable artificial object that is out of bounds; and
When out of bounds is defined by reference to stakes or a fence or as being beyond stakes or a fence, the out of bounds line is determined by the nearest inside points at ground level of the stakes or fence posts (excluding angled supports). When both stakes and lines are used to indicate out of bounds, the stakes identify out of bounds and the lines define out of bounds. When out of bounds is defined by a line on the ground, the line itself is out of bounds. The out of bounds line extends vertically upwards and downwards.
Objects defining out of bounds such as walls, fences, stakes and railings are not obstructions and are deemed to be fixed. Stakes identifying out of bounds are not obstructions and are deemed to be fixed.
Note 1: Stakes or lines used to define out of bounds should be white.
In match play, an "outside agency" is any agency other than either the player's or opponent's side, any caddie of either side, any ball played by either side at the hole being played or any equipment of either side.
The "putting green' is all ground of the hole being played that is specially prepared for putting or otherwise defined as such by the Committee. A ball is on the putting green when any part of it touches the putting green.
The term "Rule" includes:
The Rules of Golf and their interpretations as contained in "Decisions on the Rules of Golf";
The specifications on:
devices and other equipment in Appendix IV.
A "side" is a player, or two or more players who are partners. In match play, each member of the opposing side is an opponent. In stroke play, members of all sides are competitors and members of different sides playing together are fellow-competitors.
The "stipulated round" consists of playing the holes of the course in their correct sequence, unless otherwise authorized by the Committee. The number of holes in a stipulated round is 18 unless a smaller number is authorized by the Committee. As to extension of stipulated round in match play, see Rule 2-3.
A "stroke" is the forward movement of the club made with the intention of striking at and moving the ball, but if a player checks his downswing voluntarily before the clubhead reaches the ball he has not made a stroke.
A "substituted ball" is a ball put into play for the original ball that was either in play, lost, out of bounds or lifted, whether or not the substitution was permitted. A substituted ball becomes the ball in play when it has been dropped or placed (see Rule 20-4).
The "teeing ground" is the starting place for the hole to be played. It is a rectangular area two club-lengths in depth, the front and the sides of which are defined by the outside limits of two tee-markers. A ball is outside the teeing ground when all of it lies outside the teeing ground.
A "water hazard" is any sea, lake, pond, river, ditch, surface drainage ditch or other open water course (whether or not containing water) and anything of a similar nature on the course. All ground and water within the margin of a water hazard are part of the water hazard.
When the margin of a water hazard is defined by stakes, the stakes are inside the water hazard, and the margin of the hazard is defined by the nearest outside points of the stakes at ground level. When both stakes and lines are used to indicate a water hazard, the stakes identify the hazard and the lines define the hazard margin. When the margin of a water hazard is defined by a line on the ground, the line itself is in the water hazard. The margin of a water hazard extends vertically upwards and downwards.
Note 1: Stakes or lines used to define the margin of or identify a water hazard must be yellow.
A "wrong ball" is any ball other than the player's:
Ball in play includes a ball substituted for the ball in play, whether or not the substitution is permitted. A substituted ball becomes the ball in play when it has been dropped or placed (see Rule 20-4).