Definition of Set

This is a shot on the cue ball that will push through to a frozen ball on the cue ball. If the contact is made on the object ball while the cue stick is still contacting, essentially pushing the second ball, then it is usually considered a foul.

This is to lay down the money on the table in a betting game before play begins to ensure pay up at the end.

Balls remain unmoved after a player's shot.

This is a style of playing a pool game with a partner playing on your team. You can either take turns or play in a tag team style. This works well when there are a lot of people around that want to play.
A form of team play in which two players compete against another team of two players in any given frame or match. In a doubles game, the first player from the breaking team is the only one who shoots during the opening inning, with control of the table passing to a member of the opposing team at the end of that inning, then upon the end of the opponent's inning to the doubles partner of the original player, and next to the second opponent, play proceeding in this doubly alternating manner until concluded. Contrast Scotch doubles.

An imaginary line dividing the table into two equal halves lengthwise. It intersects the head string, center string and foot string at the head spot, center spot and foot spot, respectively.

The break box is a zone in the "kitchen" of the head (British: bottom) of the table, from which the break shot must be taken with the cue ball,

The lamentable practice of not following through with the cue straight, but veering off in the direction of the shot's travel or the side english is applied, away from the proper aiming line; a common source of missed shots.

Nearly table-length distance between the cue ball and target object ball, or near cue and object balls and target pocket, i.e. a potentially difficult shot ("you sure left me a lot of green on that one").
The cloth covering the table.

When the cue ball is tucked behind the corner of a pocket, therefore not allowing a direct shot at the object ball without it bouncing of the corner of the rail.

This is a shot where the cue ball double kisses in order to direct the object ball toward the pocket.

American Poolplayers Association. This is the largest association of pool players in the world, and includes The Canadian Poolplayers Association. With numerous tournaments, including the U.S. Amateur championship, they are a force on the competition scene.
The APA has established the use of the "Equalizer" which offers handicaps to players and equalizes the playing field like in golf.

Same as position. "She got good shape for the next shot". See also position play, leave.

In snooker, the highest-value colour ball on the table, being worth seven points. In some (especially American) snooker ball sets it is numbered "7" on its surface.
The black ball (usually numbered "8") in the eight-ball variant game blackball (and its variants); also the common British term for the slightly larger but otherwise identical 8 ball in a kelly pool set (a.k.a. American or WPA pool set).

"Pocket billiards," or a game in which balls are shot into pockets.

The act of setting up the balls for a break shot. In tournament play this will be done by the referee, but in lower-level play, players either rack for themselves or for each other depending on convention.

Also lows, low, low ones. In eight-ball, to be shooting the solid suit (group) of balls (1 through 7); "you're low, remember", "you're low balls" or "I've got the lows." Compare solids, reds, little, spots, dots, unders; contrast high.

In snooker, the colour ball worth 5 points, whose spot is at the center of the table.

This technique works to keep your shot aligned by eyeing your shot above the table, and then locking your chin into position as you lower down to take your shot.

Netted or cupped pockets that do not return the balls to the foot end of the table by means of a gutter system or sloped surface beneath (they must instead be retrieved manually).

A shot aimed so that the center of the cue ball is in line with the edge of the object ball, eclipsing half of the ball. "Hit it just a little thinner than half-ball." Assuming a cling does not occur, the shot will impart post-contact momentum on the object ball in a direction 30° (which is arcsin(1 - x), where x is the fraction of object ball eclipsed: ½ in this case) off the direction of the cue-ball's pre-contact momentum. Also notable because the carom angle the cue ball takes is more consistent than at other contact points.

This is the stick used to contact the cue ball in pool and billiards games. The cue stick is usually made of wood, features a special contact tip, and is usually tapered to slide through your hand. The price of these tools can range from oil change to transmission change depending on the quality of craftsmanship and design.

Same as back spin.

A cluster of balls. In snooker, the bunch of reds that are typically left below the pink spot in the early stages of a frame, not including those reds that have been released into pottable positions.

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.