Definition of head string

A line, sometimes imaginary (especially in American pool), sometimes drawn on the cloth, that runs horizontally across the table from the second diamond (from the head rail) on one long rail to the corresponding second diamond on the other long rail. In most pool games, the opening break shot must be performed with the center (base) of the cue ball behind the head string (i.e. between the head string and head rail). The head string intersects the long string at the head spot, and delimits the kitchen (and, in European nine-ball, the outer boundary of the break box). The head string's position is always determined by the diamonds, in contrast to the similar but different baulk line, the position of which is determined by measurement from the bottom cushion (head cushion).

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).
An organization that promotes competitive, usually team, amateur cue sports, most commonly pool, especially eight-ball and nine-ball, although there are also well-established snooker leagues. Some leagues, many of which are decades old, are entirely local and either informal or incorporated, and may use their own local rules or may have adopted more widely published rulesets, such as those of the WPA. Other leagues are organized on a multi-regional or even international level, and may be non-profit or for-profit enterprises, usually with their own fine-tuned rule books. Despite differences, the largest leagues are increasingly converging toward the WPA rules, with the exception of the APA/CPA, which retains rules much closer to US-style bar pool. At least four major pool leagues hold international championships in Las Vegas, Nevada annually (APA/CPA, BCAPL, VNEA and ACS/CCS). Some leagues also offer one-on-one tournaments, scotch doubles events, artistic pool competition, and other non-team activities.
This is a bank in one pocket pool that is sitting at an angle that makes it unsafe to play.
Also spot-stroke, spot hazard. A form of nurse shot in English billiards, in which the red ball, which must be spotted to a specific location after every time it is potted before another shot is taken, is potted in such as way as to leave the cue ball in position to repeat the same shot, permitting a skilled player to rack up many points in a single break (series of shots in one visit).
This is a shot in one pocket pool where you simple aim at a cluster of balls near your opponents pocket to attempt to make something good happen out of desperation because other shots are not feasible.

1- Short for "pool shark", poolshark (US); sharp, "pool sharp" (British)

2- Verb: To perform some act or make some utterance with the intent to distract, irritate or intimidate the opponent so that they do not perform well, miss a shot, etc. Most league and tournament rules forbid blatant sharking, as a form of unsportsmanlike conduct, but it is very common in bar pool.
Noun: Another term for hustler.
Noun: A very good player. This usage is common among non-players who often intend it as a compliment and are not aware of its derogatory senses .

This is the way your hand is configured to support the shaft of the cue during a shot.
This is the white ball in carom games which is separated from the clear ball by a marking (usually a dot or spot).
A (principally American) term in eight-ball for either of the set of seven balls (stripes or solids) that must be cleared before sinking the 8 ball. Borrowed from card games. Generally used in the generic, especially in rulesets or articles, rather than colloquially by players. See also group for the British equivalent.
Also known as back spin, a type of spin applied to the cue ball by hitting it below its equator, causing it to spin backwards even as it slides forward on the cloth. Back spin slows the cue ball down, reduces its travel, and narrows both the carom angle after contact with an object ball, and angle of reflection off a cushion. There are several variant terms for this, including "bottom" and "bottom spin" in the US and "screw" in the UK. Draw is thought to be the first spin technique understood by billiards players prior to the introduction of leather tips, and was in use by the 1790s.
Random method for pairing of opponents when setting up a bracket system for a tournament.
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.
When the cue ball is tucked behind the corner of a pocket, therefore not allowing a direct shot at the object ball without it bouncing of the corner of the rail.
(Chiefly British) Said of an object ball that can easily be reached by the cue ball, or of a pocket that can easily be reached by a selected object ball, usually directly (i.e. without intervening kick, bank, carom, kiss or combination shots).
This playing to a number less than eight in a game of one pocket.
In snooker, to leave the cue ball ball on the spot of a colour ball after potting it. This is usually performed where re-spotting of the colour ball would cause positional problems for the player, such as blocking available pots on one or more red balls.
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.
This is what happens when a player sends the cue ball into a cluster of balls that will in turn spread out in an unpredictable fashion.
Sometimes interchangeable with scratch, though the latter is often used only to refer to the foul of pocketing the cue ball. A violation of a particular game's rules for which a set penalty is imposed.
This refers to the distance of deflection that the ball comes off of the cue stick after a hit is applied with side spin on it.
This describes balls that are not able to be made in a pocket, either because they are high up on the table, in a different pocket, or in a cluster that makes the shot difficult. This condition of being out of play obviously exists on different difficulty levels.
Any shot where the cue ball stops immediately after hitting an object ball. Generally requires a full hit.
The inside walls of a pocket billiards table's pockets.
This is a shot where the cue ball follows directly behind the sunk object ball into the pocket right after it falls.