Also balk space.

1. An area defined on a billiard table by one or more balklines. In the eponymous game of balkline billiards , there are eight balks defined by perpendicular balklines, in which only a set number of caroms may be scored before at least one ball must leave the area. In the earlier (and short-lived) "champions' game ", there were four triangular balks, one at each corner, defined by single diagonal balklines. Not to be confused with baulk , but see second definition.
2. An area defined on a billiard table, in games such as pool, snooker , English billiards and bagatelle, by a single balkline (drawn or imaginary) that runs across the table near the head (bottom) end; exactly where depends upon table type and size. This balk is where the cue ball is placed in lagging for lead, for making the opening break shot , and sometimes for other purposes, depending upon the game . This usage of "balk" is strictly technical, and rarely used in practice. In pool, this area is called the kitchen and is divided from the rest of the table by the head string , while in snooker , English billiards and blackball it is the somewhat differently sized and delimited baulk , defined by the baulk line . On baulk tables, which have a "D" inside baulk , and on pool tables with a break box in the kitchen , the actual area from which to shoot is even smaller than the baulk or kitchen , respectively a balk within the balk .