Definition of mushroom

When the tip of the cue begins to hang over the sides of the ferrule from constant use. This is the action of mushrooming, and it is important to use a tip tool to reshape the tip to fit the ferrule.

24 Random Essential Billiards Terms

The object ball involved in a key shot.
This refers to the cluster of balls remaining in a similar position to where they were within the break.
When the cue ball contacts three or more cushions in carom games.
A shot played with stun, but not quite enough to completely stop the cue ball, allowing for a little follow. It is played so that a follow shot can be controlled more reliably, with a firmer strike than for a slow roll. It is widely considered as one of the most difficult shots in the game to master, but an excellent weapon in a player's armory once it has been.
A break shot in which the rack (pack) is disturbed as little as possible within the bounds of a legal shot, in order to force the opponent to have to break it up further. A soft break is desirable in some games, such as straight pool, in which breaking is a disadvantage; and forbidden by the open break rules of other games such as nine-ball and eight-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.
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.
The pocket chosen to house the selected ball in your called shot.
In the UK, a long-distance shot played to pot a ball close to a pocket with heavy top spin, so that when the cue ball hits the cushion it bounces off but then stops due to the counteraction of the spin. It is not common in competitive play, being more of an exhibition shot.
A shot where the shooter was trying to make the shot but misses. However, the result of the missed shot ends up being a very good defensive play.
As a result of the opening break shot (the "snap"), usually said of winning by pocketing the money ball ("won on the snap", "got it on the snap", etc.) Employed most commonly in the game of nine-ball where pocketing the 9 ball at any time in the game on a legal stroke, including the break shot, garners a win.
In blackball, a situation where the player cannot see any of the balls she/he wants to hit due to obstruction by other balls or the knuckle of a pocket. The player must call "total snooker" to the referee, which allows a dispensation to the player from having to hit a cushion after contacting the object ball, which is otherwise a foul.
In snooker, a pot into any of the corner pockets where the cue ball had started in the opposite lengthwise half of the table. In other words, a pot in which the cue ball or object ball crosses an imaginary line joining the middle pockets.
White talcum powder placed on a player's bridge hand to reduce moisture so that a cue's shaft can slide more easily. It is not provided in many establishments as many recreational players will use far more than is necessary and transfer it all over the table's surface. Venues that do provide it usually do so in the form of compress cones about 6-inches tall. Some serious players bring their own, in a bottle or a porous bag that can be patted on the bridge hand. Many players prefer a pool glove. Talc is frequently mistakenly referred to as "hand chalk", despite not being made of chalk.
A type of rest, with a straight shaft and "x"-shaped head for resting the cue upon.
This is the International Billiards and Snooker Federation. This organization governs non-professional snooker and billiards play all over the world.
To create contact with the cue ball or an object ball.
An imaginary line running horizontally across a billiards table from the second diamond (from the foot end of the table) on one long rail to the corresponding second diamond on the other long rail. The foot string intersects the long string at the foot spot. It is rarely drawn on the table.
A foul where the rules are blatantly, intentionally violated, with a stiffer penalty (e.g., loss of game) than normal.
A term used to indicate balls that are frozen, or close enough that no matter from which angle they are hit from the combination will send the outer ball the same direction. "Are the 2 and 7 pointing at the corner?? Okay, I'll use that duck to get position way over there."
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.).
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.
Also goose neck rest. Same as swan.
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.