Definition of Jam up

Same as feather (US) or snick (UK)

When the object ball lies behind another ball which makes it impossible to be struck by the cue with a direct hit.

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

To move a ball (usually deliberately) from a safe position, e.g. close to the middle of a cushion or in a cluster, so that it becomes pottable.

A low hit on the cue ball (but not as low as normal draw), often used to change the cue ball's angle of deflection off the object ball.

A player who was not shooting well during a match but suddenly turns it around and starts playing better and more accurately. Also known as "Finding a stroke" or "Found their stroke".

A pool cue designed for breaking. Along with sometimes having unusual weight or balance to build maximum speed for the cue ball, some break cues have stiffer shafts and special breaking cue tips to transfer energy more efficiently to the cue ball.

This is when you aim at one particular object ball that is not meant to go in the pocket, but is instead meant to contact another object ball which will continue the combination process or be pocketed.

A rack in the form of an equilateral triangle. There are different sizes of triangles for racking different games (which use different ball sizes and numbers of balls), including the fifteen ball racks for snooker and various pool games such as eight-ball and blackball. A larger triangle is used for the twenty-one ball rack for baseball pocket billiards). The smallest triangle rack is employed in three-ball (see illustration at that article) but is not strictly necessary, as the front of a larger rack can be used, or the balls can be arranged by hand.
The object balls in triangular formation, before the break shot, after being racked. See also pyramid.

Also bar box, pub table, tavern table. Distinctive pool tables found in bars/pubs/taverns, and often in various other venues such as family entertainment centers and arcade rooms at bowling alleys. They are almost always coin-operated and smaller than tables found in pool halls. Typical bar boxes are 3.5 ft (1.1 m) × 7 ft (2.1 m).

CPA is the acronym for the Canadian Poolplayers Association. The CPA is the Canadian league of the APA (The American Poolplayers Association)

Short for left english (side), i.e. spin imparted to the cue ball by stroking it to the lefthand side of its vertical axis. Contrast right.

To seal the pores of a wooden cue's shaft or to smooth out minor dents in the shaft by rubbing vigorously with some material.
To similarly vigorously rub the edge of a cue tip (especially a new one) to fortify it against mushrooming and ensure that it is perfectly flush with the ferrule.

Chiefly American: The cushion on the head rail. Compare bottom cushion; contrast foot cushion.

Also pro side of the pocket and missing on the professional (or pro) side of the pocket. Sometimes "of the pocket" is left off the phrase. To err on the side of overcutting a difficult corner pocket cut shot rather than undercutting in nine ball; "missing on the professional side of the pocket." So called because experienced players understand that on a thin cut, overcutting the object ball to a corner pocket will far more often leave the object ball in an unfavorable position for the incoming opponent than will an undercut, which often leaves the object ball sitting in front of or nearby the pocket it had been intended for on a miss. By contrast, in eight-ball, except when both players are shooting at the 8 ball, the incoming player after a miss is shooting for different object balls, so this maxim does not apply, and the opposite may be good strategy as, if the object ball stays near the pocket through an undercut, it is advantageously positioned for a subsequent turn and may block the opponent's use of the pocket.

Four-ball is a carom billiards game. The game is played on a pocketless table with four balls, usually one light red, one dark red, and two whites (or just two reds and two whites). Each player is assigned one of the white balls as his own cue ball. A point is scored when a shooter caroms on any two other balls. Two points are scored when the player caroms on each of the three other balls.

1- Applying very powerful follow on the cue ball thereby causing the maximum amount of follow.

2- A powerful follow shot with a high degree of top spin on it; usually when the object ball being hit is relatively close to the cue ball and is being hit very full; also known as "prograde top spin" or "prograde follow" (when referring to the action on the shot rather than the shot per se), and as a "jenny" in Australia.

The white ball struck by the cue (and so used to strike other colored, numbered, object balls) during play.

A shot in which the cue ball is potted after caroming off another ball. In snooker and most pool games doing this would be a fault (foul), but the move will score points in many games in which hazards (as such) apply, such as English billiards, or in the final or game point in Cowboy pool. The term derives from this hazard costing the player points in early forms of billiards.

Often times a protective finish is applied to a cue stick after construction. A UV polyurethane is common, and this helps to protect the cue from fading and dings.

1 - This is a shot in snooker where the cue ball follows a struck object into the pocket.

2- This is the male end of the joint located at the base of the shaft. This threaded piece, usually made of metal, connects the shaft with the forearm. The length, width, pitch and depth of threading of the pins vary from joint to joint, but most offer you a flat-faced wood-to-wood connection with the collar. This type of connection will deliver a softer hit. For a harder hit, some pins have a protruding tip without threads that directs the shaft concentrically with a pin that is buried in the collar at the joint. If you want to keep the pin of your shaft safe when your cue is dismantled, it is easy and important to use a joint protector that simply screws over your pin.

To fail to make a legal shot.

A British term describing when a ball is tight on the cushion and a player sends the cue ball to hit both the object ball and the rail at nearly the same time; the object ball, ideally, stays tight to the rail and is thus "velcroed" to the rail. Inside english is often employed to achieve this effect, hitting slightly before the ball. The movement of a ball just next to the rail (but not the shot described to achieve this movement) is called hugging the rail in both the UK and the US.