----->Torque is a measureable concept, whereas torsion is a concept, which is mathematically projected by the shear stress or the twist angle.
-----> Torque requires at least one force and torsion requires at least two forces to happen.
-----> Torque depends only on the magnitude, directions and the separation of the forces applied, while torsion depends on the torque, the type of material and the shape of the object.