or centre, in a general sense, signifies a point equally distant from the extremities of a line, figure, or body. The word is formed from the Greek κέντρον, a "point."

Center of Gravity, in mechanics, that point about which all the parts of a body do in any situation exactly balance each other. Center of Motion, that point which remains at rest, while all the other parts of a body move about it.

Center of a Sphere, a point in the middle, from which all lines drawn to the surface are equal.

Hermes Trismegistus defines God an intellectual sphere, whose center is everywhere, and circumference nowhere.