Force
In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol F.
Pound (force)
The pound of force or pound-force (symbol: lbf, sometimes lb,) is a unit of force or weight used in some systems of measurement including English Engineering units and the British Gravitational System. Pound-force should not be confused with foot-pound, a unit of energy, or pound-foot, a unit of torque, that may be written as "lbf⋅ft"; nor should these be confused with pound-mass (symbol: lb), often simply called "pound," which is a unit of mass.