Denotes the gravitational constant in mathematical notation.

G is the constant term in Newton's law of universal gravitation, which states: "The attractive force (F) between two bodies is proportional to the product of their masses (m₁ and m₂), and inversely proportional to the square of the distance (r) between them."

Not to be confused with g, the local gravitational field, which is the attractive force exerted by the Earth on a sky diver in free fall.