Definition of Head string

When the object ball lies behind another ball which makes it impossible to be struck by the cue with a direct hit.

A form of doubles play in which the two team members take turns, playing alternating shots during an inning (i.e. each team's inning consists of two players' alternating visits, each of one shot only, until that team's inning ends, and the next team begins their alternating-shot turn.) Effective scotch doubles play requires close communication between team partners, especially as to desired cue ball position for the incoming player. Like "english", "scotch" is usually not capitalized in this context. The term is also used in bowling, and may have originated there.

The ball meant to be struck and sunk in your called shot.

More commonly known as "straight pool", it was for many years the most popular game in pool and the game on which all World Championships were based.
14.1 is a call-shot game played with all 15 numbered balls and cue ball. Every ball pocketed counts as one point and a game is played to a agreed up score, generally 50, 100, or 150 points.
Traditional straight pool matches are played to 150 points.14.1 is also called "continuous pool" because, after the opening break, play continues until a player reaches the winning score. When only one numbered ball is left on the table, the remaining 14 are racked (with the apex ball missing), and play continues.

When the rules of the opening break are broken. Ex: If not enough balls contact with rails off the break.

Sometimes called spots and stripes, stripes and solids or, more rarely, bigs and littles or highs and lows.
All fifteen numbered balls are used in a conventional triangle rack.
Each player is assigned either the solid balls (1-7) or the striped balls (9-15). The object is to pocket all of your assigned balls and then pocket the 8-ball.

This is a type of shot where the cue ball goes off the rail before it heads to contact the object ball, thus giving the cue better position in some shots.

Balls remain unmoved after a player's shot.

A British term (especially in snooker) for the splitting of a group of balls when another ball is sent into them, typically with the intent of deliberately moving them with the cue ball to develop them.

Nine Ball is a rotation game so a player must hit the lowest numbered ball first.
The object of the game is pocket the 9-ball on any legal shot.

A type of spin imparted to the cue ball to make it rebound from a cushion at a shallower angle than it would if the spin had not been used.

When a particular ball is given as a handicap in nine-ball, designating that ball in turn means that it must be made in rotation, when it is the lowest numerical ball remaining on the table, and cannot be made to garner a win earlier in the game by way of a combination, carom or any other shot. For example, if a player is spotted the 8 ball, he only wins by making that ball after balls 1 through 7 have been cleared from the table.

Short for top spin, i.e. same as follow.
Chiefly British: The half of the table in which the object balls are racked (in games in which racked balls are used). This usage is conceptually opposite that in North America, where this end of the table is called the foot. In snooker, this is where the reds are racked, nearest the black spot; this is the area in which most of the game is usually played.
Chiefly American: Exactly the opposite of the above - the head end of the table. No longer in common usage.

The three-foul rule describes a situation in which a player is assessed a defined penalty after committing a third successive foul. The exact penalty, its prerequisites and whether it is in place at all, vary depending on the games. In nine-ball and straight pool, a player must be the told he is on two fouls in order to transgress the rule, and if violated, results in a loss of game for the former and a special point penalty of a loss of fifteen points (plus one for the foul itself) in the latter together with the ability to require the violator to rerack and rebreak. In Irish standard pool and English billiards, it is a loss of game if a player commits a third foul while shooting at the black. In snooker, three successive fouls from an unsnookered position result in forfeiting the frame. Repeat fouls from a snookered position are quite common - Dave Harold holds the record in a competitive match, missing the same shot 14 successive times.

A well calculated successful slop shot that is usually hit a little harder than it should be and results in a pocketed ball or two without any fouls.

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.

This is the act of disturbing you opponents good looking balls in the hope that they might move over and help you out in the game of one pocket.

A shot that only a novice or fool would take. Usually because it is a guaranteed scratch or other foul, or because it has a low percentage of being pocketed and is likely to leave the opponent in good position.

The motion of the cue stick and the player's arm on a shot;
The strength, fluidity and finesse of a player's shooting technique; "she has a good stroke."
A combination of finesse, good judgement, accuracy and confidence.

A pool room employee who plays with a good degree of skill.

Same as visit.

The table reserved for games played for money or the best table in the house. This table is always of better quality and regularly maintained. Money tables are most commonly reserved for big action.

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.