Definition of Extension

Billiard Congress of America. The official governing body for pocket billiards in the United States.

An intentionally amateurish stroke to disguise one's ability to play.

Same as center spot.

A shot in which the cue ball is driven to one or more rails (cushions in British English) before reaching its intended target-usually an object ball. Sometimes also known as "Kick Out" or "Skid" (British)

Failure to hit an object ball at all with the cue ball. In most sets of rules, this is a foul like any other. However, in some variants of bar pool a table scratch while shooting for the 8 ball is a loss of game where other more minor fouls might not be, as is scratching on the 8 ball (neither result in a loss of game in most professional rules).
By way of drift from the above definition, the term is also applied by many league players to the foul in more standardized rules of failing to drive a (any) ball to a cushion, or to pocket a legal object ball, after the cue ball's initial contact with an object ball.
By way of entirely different derivation ("scratch off the table"), it can also mean knocking the cue ball (or more loosely, any ball) completely off the table.

A fast paced offensive game similar to 9-ball but only using balls numbered 1 through 7.
Pocketing the 7-ball wins the game. Under the current pro rules of 7-ball, any missed shot gives your opponent ball-in-hand.

Same as mechanical bridge; so-called because of its typical shape.

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.

This is when a player has scratched and the foul in one pocket calls for them to spot a ball, but not able to be spotted at the time. In this case a coin is usually placed on the side of the table to keep tabs.

A tournament format in which a player is out of the tournament after a single match loss.

The use of the correct amount of cue ball speed in position play to achieve proper shape for a subsequent shot.

When you have completed a shot by pocketing a ball into a pocket.

Cueing and timing the balls well; in good form, where pocketing (potting), safety and clarity of thinking seem to come easily.

Chiefly British. This is a shot in a snooker game where the first object ball hit contacts another object ball and the second one is pocketed. If both of the balls are red, or if the second ball would be on if the first ball had not been deemed free then it is an allowed shot.

The United States Snooker Association (USSA) is the internationally recognized governing body of the sport of snooker in the United States. Founded in 1991 by the British-born Michael Collins, the USSA is a member of the International Billiards and Snooker Federation (IBSF), the world governing body of non-professional English billiards and snooker, and is affiliated with the American CueSports Alliance (ACS).

This is another name for One Pocket pool.

Chiefly British: The rail at the Top of the table. Compare foot rail; contrast Bottom rail.

This is the final object ball you need to pocket in order to win a game of one pocket.

A type of nurse used in carom billiards games. With one object ball frozen to a cushion and the second object ball just slightly away from the rail, the cue ball is gently rebounded across the face of both balls, freezing the away ball to the rail and moving the frozen ball away the same distance its partner was previously, resulting in an identical but reversed configuration, in position to be struck again by the cue ball from the opposite side.

To play a shot with the stroke and speed that makes it easiest to pocket the object ball, even at the expense of sacrificing position.

This refers to a shot that is not banked, does not hit a rail and goes into the pocket without contacting any other balls on the table.

Same as angle of reflection.

The normal phenomenon where the object ball is pushed in a direction very slightly off the pure contact angle between the two balls. Caused by the friction imparted by the first ball sliding past or rotating against the other ball.

Any shot that intentionally accounts for the elasticity of the cushions to allow a ball to bank past an otherwise blocking ball. The moving ball will sink in to the cushion very near the blocking ball giving it sufficient space to get past it or kiss off the back side of it.