balk

1. An uncultivated ridge formed in the open field system, caused by the action of ploughing.
2. The wall of earth at the edge of an excavation.
3. Beam, crossbeam; squared timber; a tie beam of a house, stretching from wall to wall, especially when laid so as to form a loft, "the balks".
4. A hindrance or disappointment; a check.
5. A sudden and obstinate stop.
6. An illegal motion by the pitcher, intended to deceive a runner.
7. A motion used to deceive the opponent during a serve.
8. The area of the table lying behind the line from which the cue ball is initially shot, and from which a ball in hand must be played.

Plural balks