Why is fixing a fractured bone called reducing the fracture?

"Reducing a fracture" is literally what you do when you "fix" a bone that is fractured.

When a bone breaks there is a "space" separating the two pieces of bone. The space, also called a "fracture", can be very small or very large but there is a space nonetheless.

To fix this bone you need to bring the two pieces back together in an anatomic position and "minimize the space" created by the break or in other Words "reduce the fracture"