Definition of defensive play

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.

24 Random Essential Billiards Terms

A shot in which if the target is missed, the opponent is safe or will not have a desirable shot;
A shot in which there are two ways to score;
A shot in which a second ball is targeted to be pocketed, broken out of a cluster, repositioned or some other secondary goal is also intended.
Also yellow(s).
In snooker, the lowest-value colour ball on the table, being worth two points. It is one of the baulk colours.
In blackball, one of two groups of seven object balls that must be potted before the eight ball; compare stripes; contrast red ball.
In the eight-ball game variant blackball, also known as eight-ball pool, a differently colored but otherwise identical replacement for the red group (i.e., what would be the solids in an American-style pool ball set).
Three Ball is a pocket billiards folk game played with three standard pool object balls and a cue ball. The goal is to pocket the three object balls in as few shots as possible.
This refers to the cluster of balls remaining in a similar position to where they were within the break.
Either of the two longer rails of a billiards or pocket billiards table, bisected by a center pocket and bounded at both ends by a corner pocket. Also called a long rail.
Any shot where the cue ball is intentionally jumped into the air to clear an obstacle
This is a shot involving contact between the cue ball and an object ball which allows the cue ball to contact another object in order to sink a pocket with the second object ball.
A term used to indicate balls that are frozen, or close enough that no matter from which angle they are hit from the combination will send the outer ball the same direction. "Are the 2 and 7 pointing at the corner?? Okay, I'll use that duck to get position way over there."
This is a handicapping method where one player gets the break, and is allowed to choose any ball afterwards to put in their pocket.
The pool player who is at the table taking their shot.
Also pills, tally balls and shake balls. Small, round markers typically numbered 1 through 15 or 16, which are placed in a bottle for various random assignment purposes, such as in a tournament roster, to assign order of play in a multiplayer game, or to assign particular balls to players in games such as kelly pool.
A thin sheet of rigid material in the size and shape of a physical ball rack (e.g. a diamond for nine-ball), with holes drilled though it, which is used to make permanent divots in the cloth of the table, one at a time for each ball in the racking pattern, by placing a ball in one of the holes in the carefully placed template and tapping it sharply from above to create the cloth indentation. The holes are spaced slightly closer than the regulation ball width of 21/2 inch (57.15 mm) apart, so that when the balls settle partially into their divots, the outer sides of these indentations create ball-on-ball pressure, pushing the balls together tightly. The purpose of the template is to do away with using a physical rack, with racking instead being performed simply by placing the balls into position, and the divots aligning them into the tightest possible formation automatically. This prevents accidental loose racks, and also thwarts the possibility of cheating by carefully manipulating the ball positions while racking. The European Pocket Billiard Federation (EPBF, Europe's WPA affiliate organization) has adopted this racking technique for its professional Euro-Tour event series.
When the tip of the cue begins to hang over the sides of the ferrule from constant use. This is the action of mushrooming, and it is important to use a tip tool to reshape the tip to fit the ferrule.
The upper portion of a cue which slides on a player's bridge hand and upon which the tip of the cue is mounted at its terminus. It also applies to the main, unsegmented body of a mechanical bridge.
To enter the loser bracket in a double elimination tournament, or otherwise slip in standing in other tournament formats (i.e., to lose a game/frame/round/match, but still remain in the competition).
This is the act of disturbing you opponents good looking balls in the hope that they might move over and help you out in the game of one pocket.
A player skilled at very thin cut shots, and shots in which a ball must pass cleanly through a very narrow space (such as the cue ball between two of the opponent's object balls with barely enough room) to avoid a foul and/or to pocket a ball. Such shots may be referred to as "surgery", "surgical shots", "surgical cuts", etc. (chiefly US, colloquial). See also feather (US) or snick (UK).
This is when a ball is spotted because of a foul or a handicap.
A British term for someone with little experience or understanding of the game, who may be skilled at potting individual balls but does not consider tactics such as position or safety; "he's a potter not a player." See also banger.
Same as visit.
A type of safety shot in the middle of a safety exchange that is not intended to put the opponent in a difficult situation regarding their next safety, but rather played so as to not leave an easy pot on. A typical example in snooker, which sees the most shots of this kind, is a slow roll-up into the pack.
Balls remain unmoved after a player's shot.
Refers to a person gambling when he has no money. As in, "That jerk can't pay up, he was shooting air barrels the whole time".