What is the difference between shaft and axle

Ideally speaking Axles are meant for balancing/transferring Bending moment and Shafts are meant for Balancing/transferring Torque.But,they can be used interchangeably also.We can have a shaft which also transmits Torque as well as Balances bending moment and in the same way an axle can also function as shaft.Such machine elements which function as axle as well as shaft are called Axleshafts.Axleshafts are designed while taking care of the acting Bending Moment as well as Torque.