Definition of open

In eight-ball, when all object balls are balls-on for either player.
A description of a break shot in which the rack (pack) is spread apart well. See also the open break requirement in some games' rules, including eight-ball and nine-ball.
In carom billiards, descriptive of play in which the balls are not gathered.

24 Random Essential Billiards Terms

American Poolplayers Association. This is the largest association of pool players in the world, and includes The Canadian Poolplayers Association. With numerous tournaments, including the U.S. Amateur championship, they are a force on the competition scene.
The APA has established the use of the "Equalizer" which offers handicaps to players and equalizes the playing field like in golf.
Confederation Panamerica of Billiards
This shot is a minimally calculated distressed shot which makes it evident to the opponent you no longer have any hope to winning the game.
Principally British: In snooker, if a player wins a match without the need for the final session to be played (for example, if a player wins a best-of-25-frames match split into three sessions - two sessions of eight frames and one of nine - by a margin of say, 13 frames to 3), then they are said to have won the match "with a session to spare".
In the eight-ball game variant blackball, also known as eight-ball pool, a differently colored but otherwise identical replacement for the red group (i.e., what would be the solids in an American-style pool ball set).
This describes a shot where you bank the object ball off of a rail and then sink it in a corner pocket.
Also pills, tally balls and shake balls. Small, round markers typically numbered 1 through 15 or 16, which are placed in a bottle for various random assignment purposes, such as in a tournament roster, to assign order of play in a multiplayer game, or to assign particular balls to players in games such as kelly pool.
This refers to how a player is playing on a particular occasion (a player's skill level). If their game is good, then they are at a high speed, but if they are not playing up to their potential, then they are playing at a lower speed.
A game that basically cannot be lost based on disparity of skill levels; "this game is a lock for him."
This is missing the fact that you owe a ball in a game of one pocket after a scratch.
A particular shot where the object ball hits or grazes another object ball on the way to its pocket or toward hitting yet another object ball.
To play for money and lull a victim into thinking they can win, prompting them to accept higher and higher stakes, until beating them and walking off with more money than they would have been willing to bet had they been beaten soundly in the beginning. The terms hustler, for one who hustles, and hustling, describing the act, are just as common if not more so than this verb form.
Chiefly American: The half of the table from which the break shot is taken. This usage is conceptually opposite that in British English, where this end of the table is called the bottom. Contrast foot. See also kitchen.
This the area behind the pocket points before the pocket. The ball can get behind here and rest waiting to be pocketed, or the cue ball can get corner hooked in this location. Different tables feature a smaller or larger area here which can make these situations more or less achievable.
An outgrowth of the training template concept, a racking template is a racking tool used in place of a traditional rigid ball rack for pool or snooker balls, consisting of a very thin, e.g. 0.14 mm (0.0055 in), sheet of material such as paper or plastic with holes into which object balls settle snugly against one another to form a tight rack (pack). The template is placed, stencil-like, in racking position, with the lead ball's hole directly over the center of the foot spot. The balls are then placed onto the template and arranged to settle into their holes, forming a tight rack. Unlike with a training template, the balls are not tapped to create divots, and instead the template is left in place until after the break shot at which time it can be removed (unless balls are still sitting on top of it). Manufacturers such as Magic Ball Rack insist that racking templates are designed "to affect the balls to a minimum", and while pro player Mike Immonen has endorsed that particular brand as a retail product, as of September 2010, no professional tours nor amateur leagues have adopted that or any other racking template. Although Magic Ball Rack implies development work since 2006, other evidence suggests invention, by Magic Ball Rack's founder, in mid 2009, with product announcement taking place in September of that year.
Chiefly American: The cushion on the foot rail. Compare top cushion; contrast head cushion.
In certain carom billiards games, any shot in which the cue ball is sucessfully caromed off an object ball to strike another object ball (with or without contacting cushions in the interim) is a considered a billiards shot.
This is a location where a player can go inexpensively to refine their pool skills. These establishments began as horserace betting houses, and are still often filled with games involving money action. If you get thirsty, many pool halls offer cold refreshments, however, be careful you are not there just for the refreshments. In that case, you may as well be playing at a bar with a bent cue on a rain table.
As in many other sports, "legal" means not causing or likely to cause a foul (the opposite being illegal). A legal hit is one in which the requirements for a non-foul hit are met (e.g., in nine-ball, the lowest-numbered ball on the table was hit by the cue ball first, and at least one object ball was pocketed, or any ball reached a cushion, after the hit on the first object ball.). A legal shot is one in which no foul of any kind was involved (e.g. there was not a double hit by the cue, the player's bridge hand did not move a ball, etc.). A legal stroke is one in which the cue stroke obeyed the rules (e.g. the shooter did not perform an illegal jump shot by scooping under the cue ball with the cue tip). A legal ball is a ball-on, an object ball at which it is permissible for the player to shoot. And so on. The term can be used in many ways consistent with these examples ("legal pocket" in one-pocket, "legal equipment" under tournament specifications, etc.).
To indicate where something is to be done. To "mark the pocket" means to indicate which pocket you intend to sink an object ball.
Deviation of a ball from its initial direction of travel. Often the result of a poor-quality table and may be an artifact of the cloth, the bed, a ball with uneven weight distribution, or simply the floor the table stands on being uneven.
The precise center of the pool table.
Describing a situation where a pot is made more difficult, either by a pocket being partially blocked by another ball so that not all of it is available, or the cue ball path to the object ball's potting angle involves going past another ball very closely.
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.