Vig (Vigorish): The small extra possibilities that affect the odds in a given situation. The extra vigorish you obtain with cube ownership is sometimes just enough to take a double.
Volatility: A measure of how likely the equity of the position can swing either way especially the larger swings and possibilities of a gammon or backgammon. A position with high volatility could have a huge equity swing favoring either player on a sequence of rolls. Volatility is one of the factors considered when offering a double.
