Aviation Dictionary
گرانیگاه، مرکز ثقل، مرکز جاذبه
The point in an object at which all of the weight is considered to be concentrated. The algebraic sum of the moments about the center of gravity is zero. The center of gravity may be expressed in inches from the datum or in percent of the mean aerodynamic chord. Center of gravity may also be thought of as the point within an object about which all the moments trying to rotate the object are balanced.