Definition of extension

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.

24 Random Essential Billiards Terms

A term used in snooker for the potting of all the balls that are racked at the beginning of the frame in a single break (run). The minimum total clearance affords 72 points (barring multiple reds being potted on a single stroke), in the pattern of red then yellow repeatedly until all reds are potted, then all of the colour balls. The maximum break is 147 (barring a foul by the opponent immediately before the break began).
When a player is on the receiving end of a devastating safety where it is very difficult or near impossible to make a legal hit on an object ball.
A situation in which a ball strikes another ball which is close to a rail and the struck ball rebounds back into the ball it was hit by; usually but not always unintended.
Displacement of the cue ball's path away from the parallel line formed by the cue stick's direction of travel; occurs every time english is employed. The degree of deflection increases as the amount of english applied increases. It is also called squirt, typically in the United States.
Shooting at an object ball that is already in motion at the moment of shooting and cue ball impact; illegal in most games and usually only seen in exhibition/trick shots.
A slang term for a cue, usually used with "piece", as in "that's a nice piece of wood".
This is what is brought to the table if you are playing at your best potential.
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.
Chiefly American: The short rail at the foot of the table. Frequently used imprecisely, to mean foot cushion. Compare top rail; contrast head rail.
With draw, as in "I shot that low left", meaning "I shot that with draw and with left english". Derives from the fact that one must hit the cue ball below it's equator, i.e. "low" on the ball, to impart draw. Contrast high.
The act of setting up the balls for a break shot. In tournament play this will be done by the referee, but in lower-level play, players either rack for themselves or for each other depending on convention.
When two objects balls are lined up so that you aim to pocket the nearest object ball, the second object ball will pocket. "That was an easy combination shot, the six ball was wired to the four ball". Also wired combination/combo, wired kiss.
A Carom game with lines drawn to form rectangles that restrict play and reduce the potential for high runs.
Three Cushion is a form of carom billiards.
The object of the game is to carom the cue ball off both object balls and contact the rail cushions at least 3 times before the last object ball. A point is scored for each successful carom.
These are fouls made in one turn and then on the next by the same player each time. Some games have a rule that a player will lose the rack or match with three succesive fouls.
A short and loose stroke performed in a manner similar to the way one throws a dart; usually employed for a jump shot. See also nip draw.
Derived from "sitting duck", usually referring to an object ball sitting close to a pocket or so positioned that is virtually impossible to miss. Same as hanger (US, colloquial), sitter (UK).
In snooker, the second-highest value colour ball, being worth six points.
A shot aimed so that the center of the cue ball is in line with the edge of the object ball, eclipsing half of the ball. "Hit it just a little thinner than half-ball." Assuming a cling does not occur, the shot will impart post-contact momentum on the object ball in a direction 30° (which is arcsin(1 - x), where x is the fraction of object ball eclipsed: ½ in this case) off the direction of the cue-ball's pre-contact momentum. Also notable because the carom angle the cue ball takes is more consistent than at other contact points.
Same as suit, predominantly in British terminology, i.e., in eight-ball either of the set of seven balls (reds or yellows) that must be cleared before potting the black. Generally used in the generic, especially in rulesets or articles, rather than colloquially by players.
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 soft joint-like plastic or linen base material. It lets the cue whip, putting more English on the cue ball.
A specific ball number followed by "out" refers to a handicap in nine-ball or other rotation games where the "spot" is all balls from that designated number to the money ball. To illustrate, the 6-out in a nine-ball game would allow the player getting weight to win by legally pocketing the 6, 7, 8 or 9 balls.
Short for run out, especially as a noun: "That was a nice out."
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.