Definition of half ball hit

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.

24 Random Essential Billiards Terms

Hitting the object ball with not enough of a cut angle; hitting the object ball too full or "fat". It is a well-known maxim that overcutting is preferable to undercutting. See also professional side of the pocket.
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."
Any shot where the cue ball is intentionally jumped into the air to clear an obstacle
A very thin cut shot in which the cue ball just brushes the edge of an object ball. "Feather" by itself can be both noun and verb (e.g. "feathering the ball").
One-pocket (often spelled one pocket) is a two-player (or -team) pocket billiards (pool) game. The object of the game is to score points by pocketing (potting) pool balls into specific pockets. A point is made when a player makes any object ball into that player's designated pocket. The winner is the first to score an agreed-upon number of points (most commonly 8). The player making the break shot (typically after winning the lag) chooses a foot corner pocket for the rest of the game; all of that shooter's balls must be shot into that pocket. All of the opponent's balls must be made in the other foot corner pocket.
Used by itself often with "low" and "high": "that's a low-percentage shot for me", "I should really take the high-percentage one".
The Billiards World Cup Association. The Billiards World Cup Association (BWA) was a governing body for carom billiards, like its competitor and successor, Union Mondiale de Billard. After staging several three-cushion billiards championships, BWA met its demise in 2004 due to financial problems and failing relations with the UMB, leaving the latter as the only carom governing body.
A ball that is easily made from many positions on the table but which is left untouched while the rack is played, so that in the event the player gets out of position, the shooter has an insurance shot. Typically an insurance ball will be in or near the jaws of a pocket.
The ball required to guarantee victory in a match. Sometimes used figuratively to mean the last difficult ball required (chiefly British and usually used in multi-frame matches, particularly snooker).
A stroking technique in which a player releases his gripping hand briefly and re-grasps the cue farther back on the butt just before hitting the cue ball.
In pool, the degree to which racked balls move apart upon impact by the cue ball as a result of a break shot.
In snooker, a shot sending the cue ball into the pack of red balls and separating them (after potting the ball-on). At least one split is usually necessary in each frame, since the original triangle of reds does not allow any balls to be potted reliably.
To sink a ball into a pocket.
A situation in which a ball strikes another ball which is close to a rail and the struck ball rebounds back into the ball it was hit by; usually but not always unintended.
This is missing the fact that you owe a ball in a game of one pocket after a scratch.
A Carom game with lines drawn to form rectangles that restrict play and reduce the potential for high runs.
Also in the zone. Describes an extended period of functioning in dead stroke ("She's in the zone").
The Higher Education Snooker and Pool Council is a voluntary, not-for-profit organisation established to promote cue sports in institutions of higher education on the island of Ireland.
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.
Principally US: One or more sets, usually in the context of gambling. See also ahead race (a.k.a. ahead session) for a more specialized usage.
Principally British: Any of a group of pre-determined frames played in a match too long to be completed within a single day's play. A best of 19 frame match, for example, is generally played with two "sessions", the first composed of nine frames, the second of ten. This term is generally used only in the context of professional snooker, as matches at the amateur level are rarely played over more than nine frames. Longer matches can be split into three or four sessions.
In the APA and CPA Leagues, session refers to the season in which League play took place. There are three sessions in each League Year-Summer Session, Fall Session and Spring Session.
A sleeve, fitted onto the lathed-down tip end of the cue, made from fiberglass, phenolic resin, brass, ivory, horn or antler, melamine, plastic, or other rigid material, upon which the cue tip is mounted and which protects the shaft wood from splitting from impact with the cue ball.
A rack in the form of an equilateral triangle. There are different sizes of triangles for racking different games (which use different ball sizes and numbers of balls), including the fifteen ball racks for snooker and various pool games such as eight-ball and blackball. A larger triangle is used for the twenty-one ball rack for baseball pocket billiards). The smallest triangle rack is employed in three-ball (see illustration at that article) but is not strictly necessary, as the front of a larger rack can be used, or the balls can be arranged by hand.
The object balls in triangular formation, before the break shot, after being racked. See also pyramid.
This is to intentionally foul by slightly moving the ball, or playing another type of illegally defensive shot in a game where the ball is just turned over to the other player. Like in one pocket, you still take the foul, but can leave the other player with a challenging shot.
This is the white ball in carom games which is separated from the clear ball by a marking (usually a dot or spot).
This is a fine powdery substance used to assist the sliding of the cue over the hand bridge.