What name is given to the white target ball in lawn bowls?

Bowls or lawn bowls is a sport in which the objective is to roll biased balls so that they stop close to a smaller ball called a "jack" or "kitty". It is played on a bowling green which may be flat (for "flat-green bowls") or convex or uneven (for "crown green bowls"). It is normally played outdoors (although there are many indoor venues) and the outdoor surface is either natural grass, artificial turf, or cotula (in New Zealand).

Lawn bowls are usually played on a large, rectangular, precisely levelled and manicured grass or synthetic surface known as a bowling green which is divided into parallel playing strips called rinks. In the simplest competition, singles, one of the two opponents flips a coin to see who wins the "mat" and begins a segment of the competition (in bowling parlance, an "end"), by placing the mat and rolling the jack to the other end of the green to serve as a target. Once it has come to rest, the jack is aligned to the centre of the rink and the players take turns to roll their bowls from the mat towards the jack and thereby build up the "head".