Centroid

In physics, the centroid of an object is either its center of mass or center of gravity. These points coincide if the object is in a uniform gravitational field.

In geometry, the centroid of a triangle is the point of intersection of its medians (the lines joining each vertex with the midpoint of the opposite side). This point is also the triangle's center of mass, if the triangle is made from a uniform sheet of material.

See also: Pappus's theorem