Backhand in the game of bowls is thumb peg.

In bowls, the way the bowl is held in the hand is called the peg. There are two types of peg: thumb peg and finger peg. The thumb peg is when the bias side of the bowl is closest to the thumb, and the finger peg is when the bias side is closest to the little finger.

A backhand delivery is when the bowl is delivered to the left of the target (for a right-handed bowler). The bias side of the bowl will cause it to curve to the right, so it is held with the thumb on the bias side. This is why a backhand delivery is also known as a thumb peg delivery.

A forehand delivery is the opposite of a backhand delivery. It is delivered to the right of the target (for a right-handed bowler) and the bias side of the bowl will cause it to curve to the left. This is why a forehand delivery is also known as a finger peg delivery.

The type of peg that is used depends on the bowler's preference and the tactical situation. For example, a backhand delivery can be used to get a bowl close to the jack, while a forehand delivery can be used to get a bowl away from the jack.

I hope this helps! Let me know if you have other questions.