1. (noun) a law stating that the ratio of the square of the revolutionary period (in years) to the cube of the orbital axis (in astronomical units) is the same for all planets

• kepler's third law

1. (noun) a law stating that the ratio of the square of the revolutionary period (in years) to the cube of the orbital axis (in astronomical units) is the same for all planets

• kepler's law
• kepler's law of planetary motion