An lb, or pound, comes from libra pondo, which is a Latin phrase that means a pound in weight. A pound or lb. is interpreted as an avoirdupois pound equivalent to the kilogram equivalent. This measurement is necessary to distinguish and compare the units used in different sections of the world. Lbf is a pound-force.
An Lbf, or a pound-force, is the gravitational force exercised by a matter on the surface of the earth. Thus, one Lbf or one pound can be gauged or converted into newtons. Lbf or - pound-force is equivalent to the product of one avoirdupois pound and the force, which is equal to the mass multiplied by the acceleration due to gravity. A pound, however, is a force, not a measurement of weight. What needs to be made clear-cut is that a pound in space is not a pound on earth, and it all depends on gravity.