Torque, moment, moment of force or "turning effect" is the rotational equivalent of linear force. The concept originated with the studies by Archimedes of the usage of levers. Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object. Another definition of torque is the product of the magnitude of the force and the perpendicular distance of the line of action of force from the axis of rotation. The symbol for torque is typically ${\\displaystyle {\\boldsymbol {\\tau }}}$, the lowercase Greek letter tau. When being referred to as moment of force, it is commonly denoted by M.