Definition of Cluster

Any shot where the cue ball is intentionally jumped into the air to clear an obstacle

Also (chiefly British) shot programme. The enumerated trick shots that must be performed in the fields of artistic billiards (70 pre-determined shots) and artistic pool (56 tricks in 8 "disciplines").

A shooter's body position and posture during a shot.

The collar is the portion of the joint that is attached to the top of the forearm. This is often stainless steel, wood, ivory, or molded phenolic resin, but in any case, made out of a solid material. This portion of the cue is glued on and threaded to reinforce the pin at the end of the shaft, and to offer a stabilized shot out of its solid construction.

On two piece cues, the area of the cue between the joint and the wrap.

This refers to a shot that is not banked, does not hit a rail and goes into the pocket without contacting any other balls on the table.

This is when you win a game of one pocket on your opponents break.

On a shot, the extension of the cue stick through the cue ball position during the end of a player's stroke in the direction originally aimed.

A directional pile created by the short fuzzy ends of fibers on the surface of cloth projecting upward from the lie and which create a favorable and unfavorable direction for rolling balls. The convention in most billiards games in which directional nap cloth is used is to brush the cloth along the table in the same direction of the nap, usually from the end that a player breaks. In snooker and UK eight-ball especially, this creates the effect of creep in the direction of the nap, the most-affected shot being a slow roll into a center pocket against the nap. It is commonly referred to in the fuller term "nap of the cloth." When nap is used in relation to woven cloths that have no directional pile, such as those typically used in the U.S. for pool tables, the term simply refers to the fuzziness of the cloth.

The World Pool-Billiard Association (WPA) is the international governing body for pocket billiards (and also sactions rules and events for carom billiards games as well, in cooperation with other bodies). The group was formed in 1987, and was initially headed by a provisional board of directors consisting of representatives from the United States, Japan, Sweden, and Germany.

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.

"Pocket billiards," or a game in which balls are shot into pockets.

Any mechanical aid that serves to extend the length of the player's cue, normally added to the end of the butt either by clipping around the end or screwing into the base. Though extensions are used for pool, it is more common in snooker because of the significantly larger table size.
In a tournament where players get limited time to make their shots (common in televised matches), an extension is extra time granted before making a shot; players have a limited number of extensions in each frame.

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

The person who is a provider of all or part of a player's stake (money) for a gambling session in which one is not a player.

Name for the ball that when pocketed, wins the game, or any ball that when made results in a payday such as a way in the game of Chicago.

Also lows, low, low ones. In eight-ball, to be shooting the solid suit (group) of balls (1 through 7); "you're low, remember", "you're low balls" or "I've got the lows." Compare solids, reds, little, spots, dots, unders; contrast high.

Named after Chicagoan J. E. Parker, it is a 3½ × 7 inch box drawn on a balkline table from the termination of a balkline with the cushion, thus defining a restricted space in which only a set number of points may be scored before one ball must be driven from the area. Now supplanted by anchor spaces, it was developed to curtail the effectiveness of the anchor nurse, which in turn had been invented to exploit a loophole in balkline rules: so long as both object balls straddled a balkline, there was no restriction on counts, as each ball lay in a separate balk space.

Ten Ball is a rotation is a rotation game very similar to nine-ball, using ten balls instead of nine, and with the 10 ball instead of the 9 as the "money ball".
The object of the game is pocket the 10-ball on any legal shot.

Also last pocket. A common rule in informal bar pool, especially bar/pub eight-ball, in which the money ball must be pocketed (potted) in the same pocket as the shooter's last object ball (each player may be said to eventually "own" a pocket, for the duration of the game, in which their 8 ball shot must be played if they have already run out their suit). The variant is not extremely common in the United States or the UK, but is near-universal in much of Latin America (where two cue ball scratches are permitted when attempting the 8 ball shot and count as simple fouls, with only a third scratch constituting a loss of game). Last pocket is also common in North Africa. Last-pocket rules require careful position play, and frequently result in bank and kick shots at the 8 ball.

Same as visit.

Local Bylaws are additional rules, policies, and procedures unique to an area in addition (or subtraction) to established Pool/Billiards/Snooker league rules. They are designed to cover local situations.

A tournament format in which a player is out of the tournament after a single match loss.

The angle from which a ball rebounds from a rail, as measured from the perpendicular to the rail.