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 point bead on a scoring string.
A player skilled at very thin cut shots, and shots in which a ball must pass cleanly through a very narrow space (such as the cue ball between two of the opponent's object balls with barely enough room) to avoid a foul and/or to pocket a ball. Such shots may be referred to as "surgery", "surgical shots", "surgical cuts", etc. (chiefly US, colloquial). See also feather (US) or snick (UK).
A rule in blackball whereby after an opponent has faulted and thus yielded two shots, if the incoming shooter pots a ball on the first shot, (s)he is still allowed to miss in a later shot and take a second shot in-hand (from the "D" or from baulk, or if the opponent potted the cue ball, from anywhere)—even on the black, in most variants. Also called the "two visits" rule; i.e., the two penalty shots are considered independent visits to the table, and the limiting variants discussed at two shots below cannot logically apply.
To play for money and lull a victim into thinking they can win, prompting them to accept higher and higher stakes, until beating them and walking off with more money than they would have been willing to bet had they been beaten soundly in the beginning. The terms hustler, for one who hustles, and hustling, describing the act, are just as common if not more so than this verb form.
Inadvertent english placed on the cueball by a failure to hit it dead center on its horizontal axis. It is both a common source of missed shots and commonly overlooked when attempts are made to determine the reason for a miss. In UK parlance this is usually called 'unwanted side'.
A joint type which makes it possible to screw and unscrew the butt and shaft very quickly; faster than standard threads.
A three cushion billiards shot in which the cue ball first strikes two cushions before hitting the first object ball then hits a third cushion before hitting the second object ball. So called because the shot opens up like an umbrella after hitting the third rail. Umbrella shots may be classified as inside or outside depending on which side of the first object ball the cue ball contacts.
When a successful non penalized break is achieved which gives the object balls a broad spread on the table.
Same as centre pocket.
A type of nurse shot used in English billiards in which two coloured balls are positioned on either side of the mouth of a snooker table pocket but not touching and, thus placed, can be successively contacted and scored off over and over by the cue ball without moving them.
This is a particular ball which lends itself to be used as a "blocker" or a "protector."
To use a particular ball as security by playing a safety or leaving it where it will act as one.
In snooker, the colour ball that is worth three points, being the second-least valuable colour behind the yellow. It is one of the baulk colours.

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.

Principally British: In snooker, if a player wins all of the required frames in a match without conceding a frame to their opponent - for example, if a player wins a best-of-nine-frame match with a score of 5-0 - this is referred to as a "whitewash". This term is based on a similar term used in the card game of "patience" in the UK. However, it is not used in the context of a 1-0 winning scoreline in a match consisting of a single frame.
A material, usually leather, placed on the end of a cue stick that comes in contact with the cue ball.

1- Noun: A player's wager in a money game.

2- Verb:To provide part or all of a player's stake for a gambling session in which one is not a player. A person who stakes or backs a player is called a stakehorse or backer. "Stakehorse" can also be used as a verb.

Also treble. A British term for a type of bank shot in which the object ball is potted off two cushions, especially by sending it twice across the table and into a side pocket. Also called a two-cushion double.
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.
Exact opposite of fast, all senses.
This is a simple method of gambling where bets are determined between each game instead of playing matches.
Actual wire or string with multiple beads strung (like an abacus) used for keeping score. Points "on the wire" are a type of handicap used, where a weaker player will be given a certain number of points before the start of the game.
This is a ball that is resting on the edge of a pocket, and would be a very easy shot to pocket.
This is also used to describe the ball when it rests on the edge of the pocket, almost begging to drop.
Describing a pot played at such a pace as to just reach the pocket and drop in without hitting the back.
Also dead ball shot. A shot intended to slow down or "kill" the cue ball's speed as much as possible after contact with an object ball; usually a shot with draw, often combined with inside english. It is often shortened to kill.