Definition of Button

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 to direct the cue ball by barely contacting an object ball.

You can cheat the pocket by angling your shot to go in at the right or left of the pocket opening when sinking a shot. This permits the cue ball to strike the object ball at a different contact point than the most obvious one.

Describes the propensity of pockets to more easily accept an imperfectly aimed ball shot at a relatively soft speed, that might not fall if shot with more velocity ("that ball normally wouldn't fall but he hit it at pocket speed"). The less sensitive to shot-speed that a pocket is, the "faster" it is said to be.
Describes the velocity of an object ball shot with just enough speed to reach the intended pocket and drop. "Shoot this with pocket speed only, so you don't send the cue ball too far up-table."

When the object ball banked of a rail goes directly in a pocket without kissing or touching any other object balls.

Exact opposite of fast, all senses.

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.

In the UK, one of the two pockets one either side of a pool, snooker or English billiards table halfway up the long rails.

Inadvertent english placed on the cueball by a failure to hit it dead center on its horizontal axis. It is both a common source of missed shots and commonly overlooked when attempts are made to determine the reason for a miss. In UK parlance this is usually called 'unwanted side'.

Chiefly British: The half of the table from which the break shot is taken. This usage is conceptually opposite that in North America, where this end of the table is called the head.

Be in a game where either because of disparity in skill level, or because of a handicap given, it would be very difficult to lose.

A semicircle with an 11½ inch (291 mm) radius, drawn behind a snooker table's baulk line, centred on the middle of the line, and resembling the upper case letter "D" in shape. The "D" is also used in English billiards and sometimes also in blackball and other pool games played on British-style tables.

This is to step up to the table and successfully execute a difficult shot.

Chiefly British: The rail at the Top of the table. Compare foot rail; contrast Bottom rail.

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

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.

A line, sometimes imaginary (especially in American pool), sometimes drawn on the cloth, that runs horizontally across the table from the second diamond (from the head rail) on one long rail to the corresponding second diamond on the other long rail. In most pool games, the opening break shot must be performed with the center (base) of the cue ball behind the head string (i.e. between the head string and head rail). The head string intersects the long string at the head spot, and delimits the kitchen (and, in European nine-ball, the outer boundary of the break box). The head string's position is always determined by the diamonds, in contrast to the similar but different baulk line, the position of which is determined by measurement from the bottom cushion (head cushion).

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.

Also the hook. In snooker, a type of mechanical bridge that has only recently been endorsed by the WPBSA to allow its use in major tournament play. It is a normal rest with the head in line with the shaft, but the last foot or so of the shaft is curved. This allows players to position the curved end around an obstructing ball that would have otherwise left them hampered on the cue ball and in need of a spider or swan with extensions, which would have less control.

Also nurse shot, nursery shot. In carom games such as straight rail, balkline and cushion caroms, where all the balls are kept near each other and a cushion, and with very soft shots, can be "nursed" down a rail on multiple successful shots that effectively replicate the same ball setup so that the nurse shot can be repeated again (and again, etc.). Excessive use of nurse shots by players skilled enough to set them up and pull them off repeatedly at will is what led to the development of the balkline carom billiards game variations, and repetitive shot limitation rules in English billiards. A clear example of why: In 1907, Tom Reece scored a record break of 499,135 consecutive points over a period of five weeks, without a miss, using the cradle cannon nurse shot.

In snooker, the cushion opposite the top cushion and bounded by the yellow and green pockets (i.e. same as bottom cushion).

Describes lucky or unlucky "rolls" of the cue ball; "I had good rolls all night; "that was a bad roll." However, when said without an adjective ascribing good or bad characteristics to it, "roll" usually refers to a positive outcome such as in "he got a roll".
The roll: same as the lag.

The angle from which a ball rebounds from a rail, as measured from the perpendicular to the rail.

Same as gapper