The point in a system of masses each of whose coordinates is a weighted mean of coordinates of the same dimension of points within the system, the weights being determined by the density function of the system.
A point whose coordinates are the averages of the corresponding coordinates of a given set of points and which for a given plane or three-dimensional figure (as a triangle or sphere) corresponds to the of mass of a thin plate of uniform thickness and consistency or a body of uniform consistency having the same boundary.