Definition of illegal

Anything that causes a foul according to the rules of a game.

24 Random Essential Billiards Terms

To intentionally miss a shot (that results in a foul) in order to create a position for the cue ball that makes it hard for the other player to execute their shot. Not to be confused with a "Safety", since a safety is a legal hit.
To bungle a shot in a manner that leaves the table in such a fortuitous position for the opponent that there is a strong likelihood of losing the game or match. Contrast sell out.
The ball required to guarantee victory in a match. Sometimes used figuratively to mean the last difficult ball required (chiefly British and usually used in multi-frame matches, particularly snooker).

1- Noun: A player's wager in a money game.

2- Verb:To provide part or all of a player's stake for a gambling session in which one is not a player. A person who stakes or backs a player is called a stakehorse or backer. "Stakehorse" can also be used as a verb.

To give a handicap to an opponent where they have to win a specified number less games than the other player in order to triumph in the match. The name refers to posting games on the scorekeeping mechanism known as a wire, though it is employed when no actual use of the particular device is available or intended.
A defensive action taken when a player either has no "makeable" or "high percentage" shot or chooses to leave his opponent in a difficult situation. It is a legal shot and is not considered to be dirty pool. A safety must still conform with the rule concerning hitting the correct ball first and striking a rail afterwards. If a correct ball is accidentally pocketed while playing safe, the shooter must continue to shoot.
Also shot to nothing. A British term for a shot in which a player attempts a difficult pot but with safety in mind, so that in the event of missing the pot it is likely that the opponent will not make a meaningful contribution, and will probably have to reply with a safety. The meaning refers to lack of risk, i.e. at no cost to the player ("for nothing" or coming "to nothing"). Compare two-way shot.
Also winner. A shot in which the cue ball is used to pot another ball. In snooker and most pool games doing this is known as potting, pocketing or sinking the targeted ball. The term derives from this hazard winning the player points, while losing hazards cost the player points, in early forms of billiards. Whether the ball is an object ball or an opponent's cue ball depends upon the type of game (some have two cue balls). The move will score points in most (but not all) games in which hazards (as such) apply, such as English billiards (in which a "red winner" is the potting of the red ball and a "white winner" the potting of the opponent's cue ball, each worth a different amount of points).
This is a tip tool for cleaning the edges of you tip after mushrooming occurs.
A cut shot in which if a line were drawn from the cue ball to the rail behind the targeted object ball, perpendicular to that rail, the object ball would lie beyond the line with respect to the pocket being targeted.
Oceania Pocket Billiard Association.
Term for object balls in the game of Chicago that are each assigned as having a set money value; typically the 5, 8, 10, 13 and 15. In games where multiple balls must be pocketed in succession to score a point, such as cribbage pool or thirty-ball, when the last ball necessary to score has been potted, the points given is referred to as a way.
A material, usually leather, placed on the end of a cue stick that comes in contact with the cue ball.
Also bar rules, pub pool, tavern pool. Pool, almost always a variant of eight-ball, that is played by bar players on a bar table. Bar pool has rules that vary from region to region, sometimes even from venue to venue in the same city, especially in the U.S. Wise players thus ensure understanding of and agreement to the rules before engaging in a money game under bar rules. Typical differences between bar pool and tournament eight-ball are the lack of ball-in-hand after a foul, the elimination of a number of fouls, and (with numbered ball sets) the requirement that most aspects of a shot be called (including cushions and other object balls to be contacted) not just the target ball and pocket. Bar pool has evolved into this "nitpicky" version principally to make the games last longer, since bar pool is typically played on coin-operated tables that cost money per-game rather than per-hour. Competitive league pool played on bar tables, however, usually uses international, national or local/regional league rules, and is not what is usually meant by "bar pool".
An instance of contact between balls, usually used in the context of describing an object ball contacting another object ball (e.g. "the two ball kissed off the twelve ball"), or in snooker the cue ball making contact with a ball after the initial contact with the object ball. If the player's intention was to cause two object balls to kiss (e.g. to pocket a shot ball after a ricochet off a stationary one), it is often called a kiss shot.
A player's auction at a pool tournament. Each player is called and players and spectators bid on the player. The highest bidder(s) pays their bid to the calcutta, and by doing so invest in that player's success. If a player wins or places in the tournament, those who "bought" the player receive a percentage of the total calcutta payout, usually tracking the percentage payout of the tournament prize fund. Typically, players have the option of purchasing half of themselves when the high bid is won by a third party. Like english and scotch doubles, usually not capitalized.
Same as break.
Either of the two shorter rails on a standard pool, billiards or snooker table. Contrast side rail/long rail.
This refers to a ball that is positioned close to a rail, offering a shot where the cue must hit the rail and the ball almost simultaneously, this position can also offer a defensive shot where the cue ball can be hidden between that object ball and the rail.
Used in snooker in reference to the position of the cue ball. It is above the object ball if it is off-straight on the baulk cushion side of the imaginary line for a straight pot (e.g. "he'll want to finish above the blue in order to go into the pink and reds"). It is also common to use the term high instead.
Describes a player who needs only one more game win to be victorious in the match.
Also nurse shot, nursery shot. In carom games such as straight rail, balkline and cushion caroms, where all the balls are kept near each other and a cushion, and with very soft shots, can be "nursed" down a rail on multiple successful shots that effectively replicate the same ball setup so that the nurse shot can be repeated again (and again, etc.). Excessive use of nurse shots by players skilled enough to set them up and pull them off repeatedly at will is what led to the development of the balkline carom billiards game variations, and repetitive shot limitation rules in English billiards. A clear example of why: In 1907, Tom Reece scored a record break of 499,135 consecutive points over a period of five weeks, without a miss, using the cradle cannon nurse shot.
Also slop shot. A luck shot. Compare fish, fluke and Lorengo; contrast mark and call. Also sloppy. Descriptive of any game where the rules have been varied to allow luck shots not normally allowed or where no foul rules apply.
A type of rest, with a straight shaft and "x"-shaped head for resting the cue upon.