Definition of Unders

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.

Side spin on the cue ball that causes it to roll off a cushion (contacted at an angle) with rather than against the ball's natural momentum and direction of travel. If angling into a rail that is on the right, then running english would be left english, and vice versa. The angle of deflection will be wider than if no english were applied to the cue ball. But more importantly, because the ball is rolling instead of sliding against the rail, the angle will be more consistent. For this reason, running English is routinely used. Also called running side in British terminology. Contrast reverse english.

In snooker, a shot where a player fouls by missing the ball on altogether. The miss rule allows for his opponent to have the player play exactly the same shot again, or at least as accurately as the referee is able to reproduce the ball positions. A miss usually occurs when a player makes an unsuccessful attempt at escaping from a snooker. It is a controversial rule aimed at formally discouraging deliberate fouls. In professional snooker, a referee will almost always call a miss on any foul where the player misses the ball on altogether, regardless of how close the player comes to hitting it, however no miss can be called when either of the players requires snookers to win the frame. If a player is called for a miss three times in a single visit while not snookered, he forfeits the frame; to avoid this, players almost always play an easy hit on their third attempt, even if it is likely to leave a chance for the opponent.

The full fifteen ball set of pool or snooker object balls after being racked, before the break shot (i.e., same as rack, definition 2, and triangle, defn. 2). Chiefly British today, but also an American usage ca. World War I.

This is a method of handicapping that designates a wild ball for a lesser player to be able to pocket at any point during a game in order to win.

Chiefly American: The short rail at the head of the table. Traditionally this is the rail on which the table manufacturer's logo appears. Compare bottom rail, baulk rail; contrast foot rail.

The pool player who is at the table taking their shot.

The person in charge of the game whose primary role is to ensure adherence by both players to the appropriate rules of the game being played. Other duties of the referee include racking each frame, re-spotting balls during the course of a game, maintaining the equipment associated with the table (e.g. keeping the balls clean), controlling the crowd and, if necessary, controlling the players. Formerly sometimes referred to as the umpire.

Also simply maximum. In snooker, the highest break attainable with the balls that are racked; usually 147 points starting by potting fifteen reds, in combination with blacks, and clearing the colours. Also called a 147 (one-four-seven). In six-red snooker, the maximum break is only 75 points, due to fewer red balls and thus fewer black-scoring opportunities.

English Amateur Billiards Association. The EABA is the governing body of amateur billiards in England, and as such is responsible for organizing various tournaments and events.

This is your pocket for sinking balls in a one pocket game.

This is to miss your shot but either luckily or on purpose leave your opponent with nothing to shoot at.

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.

Same as center spot.

This is a ball that is left in a position that allows an easy shot, while time is spent working with other balls to better your position in the game.

Principally US: One or more sets, usually in the context of gambling. See also ahead race (a.k.a. ahead session) for a more specialized usage.
Principally British: Any of a group of pre-determined frames played in a match too long to be completed within a single day's play. A best of 19 frame match, for example, is generally played with two "sessions", the first composed of nine frames, the second of ten. This term is generally used only in the context of professional snooker, as matches at the amateur level are rarely played over more than nine frames. Longer matches can be split into three or four sessions.
In the APA and CPA Leagues, session refers to the season in which League play took place. There are three sessions in each League Year-Summer Session, Fall Session and Spring Session.

This is a shot involving contact between the cue ball and an object ball which allows the cue ball to contact another object in order to sink a pocket with the second object ball.

A sleeve, fitted onto the lathed-down tip end of the cue, made from fiberglass, phenolic resin, brass, ivory, horn or antler, melamine, plastic, or other rigid material, upon which the cue tip is mounted and which protects the shaft wood from splitting from impact with the cue ball.

Also massé shot. A steep curve or complete reversal of cue ball direction without the necessity of any rail or object ball being struck, due to extreme spin imparted to the cue ball by a steeply elevated cue. For Example: shooting with extreme english by holding the cue at a position of 30-90 degrees while applying left or right spin.

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.

This is how the player is who is does not break before they get a chance to get out of the break. This time period is when the breaking player with a position advantage on the table.

The area on the table behind the head string.
The origin of the term has been the subject of some speculation but the best explanation known is that in the 1800s, many homes did not have room for both a billiard table and a dining room table. The solution was a billiards table that had a cover converting it into a dining table. Kept in the dining room, play on such a table was often restricted by the size of the room, so it would be placed so that the head rail would face the connected kitchen door, thus affording a player room for the backswing without hitting a wall. A player was therefore either half or sometimes fully (literally) "in the kitchen" when breaking the balls.

Also the hook. In snooker, a type of mechanical bridge that has only recently been endorsed by the WPBSA to allow its use in major tournament play. It is a normal rest with the head in line with the shaft, but the last foot or so of the shaft is curved. This allows players to position the curved end around an obstructing ball that would have otherwise left them hampered on the cue ball and in need of a spider or swan with extensions, which would have less control.

This refers to the cluster of balls remaining in a similar position to where they were within the break.