The distance from the string to the deepest part of the handle or grip. This distance can be changed by twisting the string tighter to increase the height and untwisting it to decrease the height.

Is the length of a direct line from the back of the grip to the string of a bow. Generally, the lower the brace height, the faster the bow is. It is faster because the shorter brace height means that the power stroke is longer. But, because a shorter brace height gives you a longer power stroke it can be much more difficult to shoot accurately.