Definition of Green ball

Used by itself often with "low" and "high": "that's a low-percentage shot for me", "I should really take the high-percentage one".

This is a kind of cue made of only two pieces of wood, and joined together using an advanced adhesive along the points of the cue. This connection gives the cue a flawless look and a fluid feel when shooting.

To intentionally lose a game, e.g. to disguise one's actual playing ability. An extreme form of sandbagging. See also hustle. See also Match fixing for the synonym "tank", used in sports more generally.

This is a kind of cue made of four pieces of wood, the butt sleeve, the points, the handle, and the forearm, with each piece pinned, doweled, and glued together.

To win an inning that counters a good game your opponent just won.
The inning win that counters a good game your opponent just won.

Also straight eight-ball. Same as bar pool. Not to be confused with the games of straight pool or straight rail.

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.

Four-ball is a carom billiards game. The game is played on a pocketless table with four balls, usually one light red, one dark red, and two whites (or just two reds and two whites). Each player is assigned one of the white balls as his own cue ball. A point is scored when a shooter caroms on any two other balls. Two points are scored when the player caroms on each of the three other balls.

Also Gentleman's call. An informal approach to the "call-everything" variation of call-shot, common in bar pool. Obvious shots, such as a straight-on or near-straight shot for which the shooter is clearly aiming and which could not be mistaken for another shot, need not be called. Bank shots, kicks, caroms and combinations are usually less obvious and generally must be called, though this may depend upon the mutual skill level and shot selection perception of the players. An opponent has the right to ask what the shooter's intention is, if this is unclear.

All-Africa Pool Association. The AAPA is a member of the WPA.

Chiefly British: The cushion on the top rail. Compare foot cushion; contrast bottom cushion.

Chiefly American: The short rail at the foot of the table. Frequently used imprecisely, to mean foot cushion. Compare top rail; contrast head rail.

This is a shot that is meant to remove one of your opponent's balls that lies near their pocket in the game of one pocket.

Either of the two shorter rails of a billiards or pocket billiards table.

This is the apex ball in the triangle, racked on the foot spot in a normal game.

Also bigs, big balls, big ones. In eight-ball, to be shooting the striped suit (group) of balls (9 through 15); "you're big, remember", "you're big balls" or "I've got the big ones". Compare stripes, yellows, high, overs; contrast little.

This is when you win a game of one pocket on your opponents break.

A stroke in which the cue's tip glances or slips off the cue ball not effectively transferring the intended force. Usually the result is a bungled shot. Common causes include a lack of chalk on the cue tip, a poorly groomed cue tip and not stroking straight through the cue ball, e.g. because of steering.

The overall competition between two players, two pairs of players or two teams of players, usually consisting of a predetermined number of frames or games (sometimes organized into rounds).

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.

Named after Chicagoan J. E. Parker, it is a 3½ × 7 inch box drawn on a balkline table from the termination of a balkline with the cushion, thus defining a restricted space in which only a set number of points may be scored before one ball must be driven from the area. Now supplanted by anchor spaces, it was developed to curtail the effectiveness of the anchor nurse, which in turn had been invented to exploit a loophole in balkline rules: so long as both object balls straddled a balkline, there was no restriction on counts, as each ball lay in a separate balk space.

Used when describing perfect cue ball position play.

This is the International Billiards and Snooker Federation. This organization governs non-professional snooker and billiards play all over the world.

This is the act of keeping your ball location advantages the way they are, and not allowing your opponent to even things out in the game of one pocket.