Definition of safety

A defensive action taken when a player either has no "makeable" or "high percentage" shot or chooses to leave his opponent in a difficult situation. It is a legal shot and is not considered to be dirty pool. A safety must still conform with the rule concerning hitting the correct ball first and striking a rail afterwards. If a correct ball is accidentally pocketed while playing safe, the shooter must continue to shoot.

24 Random Essential Billiards Terms

To elevate the back of the cue on a shot.
To sink a ball into a pocket.
Also known as Free-stroking. This is slang for when a player begins to play untroubled and relaxed because they have built up a substantial lead.
This is the act of looking over the stack, pile of balls in the middle of the table, to see if there are any opportunities in the game of one pocket.
The game of snooker. This is a very demanding game that isn't played as often in the U.S. as it is in other countries. The table needed is slightly larger, and there are 15 red object balls needed in addition to six color balls. After the balls are set up according to the rules, play resumes in turns with points scored as one on each red ball, and as is denoted with each other colored ball sunk. This is a challenging game that demands skill and excellent execution.
To leave the opponent (accidentally or by means of a safety) so that a certain shot on a preferred object ball cannot be played directly in a straight line by normal cueing. It most commonly means that the object ball cannot be hit, because it is hidden by another ball or, more rarely, the knuckle of a pocket (see corner-hooked). It can also refer to the potting angle or another significant point of contact on the object ball, blocking an otherwise more straightforward shot, even if an edge can be seen. A common related adjective describing a player in this situation is snookered. Also known as "to hook", for which the corresponding adjective "hooked" is also common. See also free ball.
An instance of this situation (e.g. "she's put him in a difficult snooker"). A player can choose a range of shots to get out of a snooker; usually a kick shot will be implemented but semi-massés are often preferred, and in games where it is not a foul, jump shots may be employed that often yield good results for skilled players. "Snooker" is used loosely (when used at all; "hook" is favored) in the US, but has very specific definitions and subtypes (such as the total snooker) in blackball.
A British term for someone with little experience or understanding of the game, who may be skilled at potting individual balls but does not consider tactics such as position or safety; "he's a potter not a player." See also banger.
The pocket in snooker that is closest to the green spot.
Given to the opposite player after a scratch on the cue ball has been played. This means the player with the cue ball in hand can position it wherever on the table he pleases. Sometimes there are restrictions as to where on the table the ball can be placed: in the kitchen, within the half circle, within the D. This is also known as cue ball in hand.
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.
Also simply maximum. In snooker, the highest break attainable with the balls that are racked; usually 147 points starting by potting fifteen reds, in combination with blacks, and clearing the colours. Also called a 147 (one-four-seven). In six-red snooker, the maximum break is only 75 points, due to fewer red balls and thus fewer black-scoring opportunities.
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 the ball that sits in the front, or apex, position in the rack.
The deciding match between two tied opponents. Compare hill, hill.
Also slop shot. A luck shot. Compare fish, fluke and Lorengo; contrast mark and call. Also sloppy. Descriptive of any game where the rules have been varied to allow luck shots not normally allowed or where no foul rules apply.
Any one of numerous acts which unethical players employ to rattle or upset their opponent. Taking, making noise, and chalking your cue while your opponent is shooting are all considered sharking tactics.
A predetermined, fixed number of games players must win to win a match; "a race to seven" means whomever wins seven games first wins the match.

An attempt of a legal clean shot (not a slop shot) that goes badly wrong due to improper stroke, stance, table position or table conditions in which the result of the shot is completely unexpected and not what was predicted at all.

This is an imaginary line that separates the halves of the table by crossing at the middle of the side of pockets.
A player who was playing very well but suddenly starts playing badly. e.g. "He was making everything on every shot, then lost his stroke and couldn't hit anything, costing him the match."
Same as gapper
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.
A style of game play in which as many players are allowed to join as the participants choose, and anyone can quit at any time. The term, most often used in the context of gambling, is borrowed from poker. The folk games three-ball and killer are usually played as open ring games, as is Kelly pool.
By extension, a multi-player game that anyone may initially join, but which has a fixed roster of competitors once it begins, is sometimes also called a ring game. Cutthroat is, by its nature, such a game. A famous regular ring game event of this sort is the Grady Mathews-hosted six-player, $3000-buy-in ring ten-ball competition at the annual Derby City Classic.
A nine-ball ring game is played by more than two players. Safeties are not allowed.
The area on the table behind the head string.
The origin of the term has been the subject of some speculation but the best explanation known is that in the 1800s, many homes did not have room for both a billiard table and a dining room table. The solution was a billiards table that had a cover converting it into a dining table. Kept in the dining room, play on such a table was often restricted by the size of the room, so it would be placed so that the head rail would face the connected kitchen door, thus affording a player room for the backswing without hitting a wall. A player was therefore either half or sometimes fully (literally) "in the kitchen" when breaking the balls.
Chiefly American: Also known as side spin, english (which is usually not capitalized) is spin placed on the cue ball when hit with the cue tip to the left or right of the ball's center. English has a marked effect on cue ball rebound angle off cushions (though not off object balls), and is thus crucial for gaining shape; and can be used to "throw" an object ball slightly off its otherwise expected trajectory, to cheat the pocket, and for other effects. "English" is sometimes used more inclusively, to colloquially also refer to follow and draw. In combination one could say bottom-right english, or like the face of a clock (4 o'clock english). The British and Irish do not use this term, instead preferring "side".