Definition of legal

As in many other sports, "legal" means not causing or likely to cause a foul (the opposite being illegal). A legal hit is one in which the requirements for a non-foul hit are met (e.g., in nine-ball, the lowest-numbered ball on the table was hit by the cue ball first, and at least one object ball was pocketed, or any ball reached a cushion, after the hit on the first object ball.). A legal shot is one in which no foul of any kind was involved (e.g. there was not a double hit by the cue, the player's bridge hand did not move a ball, etc.). A legal stroke is one in which the cue stroke obeyed the rules (e.g. the shooter did not perform an illegal jump shot by scooping under the cue ball with the cue tip). A legal ball is a ball-on, an object ball at which it is permissible for the player to shoot. And so on. The term can be used in many ways consistent with these examples ("legal pocket" in one-pocket, "legal equipment" under tournament specifications, etc.).

24 Random Essential Billiards Terms

The triangular device, generally plastic, used to group the balls in a pyramid form prior to the beginning of a game.
Side spin on the cue ball that causes it to roll off a cushion (contacted at an angle) with rather than against the ball's natural momentum and direction of travel. If angling into a rail that is on the right, then running english would be left english, and vice versa. The angle of deflection will be wider than if no english were applied to the cue ball. But more importantly, because the ball is rolling instead of sliding against the rail, the angle will be more consistent. For this reason, running English is routinely used. Also called running side in British terminology. Contrast reverse english.
This is a blemish added to the table in order to help execute a shot; these marks are not allowed and result in a foul.
The point on the table surface over which the apex ball of a rack is centered (in most games). It is the point half the distance between the long rails' second diamonds from the end of the racking end of the table. The foot spot is the intersection of the foot string and the long string, and is typically marked with a cloth or paper decal on pool tables.
This is a shot where the cue ball contacts an object ball and moves it along a path, but because the cue ball is still in motion it re-contacts the object ball and pushes it in the pocket after it stops.
This refers to the cluster of balls remaining in a similar position to where they were within the break
Sandbagging, in any handicapped sport, is the unethical practice of deliberately playing below your ability in order to alter your handicap so it does not reflect your true ability.
The ornamentation on a cue is often made by inlaying exotic materials into the wood of the butt portion of the cue. Inlays of ebony and ivory are quite common. The value of a cue is often based on the number inlays.
This is playing to a higher winning score than eight in the game of one pocket.
This is a play where the shot of the cue ball is meant to end up in a certain place to loose your turn, but makes the next attempt difficult for your opponent. The shot is turned over, but will often times lead to a foul, giving you the ball back with a different view or ball in hand. This "safety" play is important if your shot isn't ideal, and you are likely to turn the ball over anyway.
A term applied especially in snooker for a type of double off three cushions, e.g. around the baulk colours and into a centre pocket. Such a shot is very difficult to make and would not normally be played as anything more than a shot for nothing.
Also littles, little ones, little balls. In eight-ball, to be shooting the solid suit (group) of balls (1 through 7); "you're little, remember", "you're the little balls" or "I've got the littles". Compare small, solids, reds, low, spots, dots, unders; contrast big.
In snooker, a pot into any of the corner pockets where the cue ball had started in the opposite lengthwise half of the table. In other words, a pot in which the cue ball or object ball crosses an imaginary line joining the middle pockets.
"Pocket billiards," or a game in which balls are shot into pockets.
This is the way a ball rolls when impeded by something on the table or a blemish in the cloth, often times regular players will remember certain rolls and play to them.
A shot in which the cue ball is struck above its equator with sufficient top spin to cause the cue ball to travel forward after it contacts an object ball. When a cue ball with follow on it contacts an object ball squarely (a center-to-center hit), the cue ball travels directly forward through the space previously occupied by the object ball (and can sometimes even be used to pocket a second ball). By contrast, on a cut shot, a cue ball with follow on it will first travel on the tangent line after striking the object ball, and then arc forward, widening the carom angle.
A particular shot where the object ball hits or grazes another object ball on the way to its pocket or toward hitting yet another object ball.
Technique using different wood inlays to create picture designs on the butt of the cue.
This is the final object ball you need to pocket in order to win a game of one pocket.
The effect of shooting regulation-weight object balls with an old-fashioned over-weight bar table cue ball, such that the cue ball moves forward to occupy (sometimes only temporarily), or go beyond, the original position of the object ball, even on a draw or stop shot, because the mass of the cue ball exceeds that of the object ball. Players who understand smash-through well can use it intentionally for position play, such as to nudge other object balls nearby the target ball. Smash-through also makes it dangerous in bar pool (when equipped with such a cue ball) to pocket straight-on ducks with a stop shot instead of by cheating the pocket because of the likelihood of scratching the cue ball.
A natural is an easy shot requiring no side spin. A shot is said to be natural if it does not require adjustments, such as a cut angle, side spin, or unusual force. A natural bank shot, for example, is one in which simply shooting straight into the object ball at medium speed and with no spin will send the object ball directly into the target pocket on the other side of the table.
Also solid, solid ones, solid balls. The non-striped ball suit (group) of a fifteen ball set that are numbered 1 through 7 and have a solid color scheme (i.e., not including the 8 ball). As in, "I'm solid", or "you've got the solids". Compare low, small, little, reds, spots, dots, unders; contrast stripes.
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.
Chiefly American, and largely obsolete: Same as referee.