ˈkeplə(r)z- noun
Usage: usually capitalized K
Etymology: after Johannes Kepler
1. : a statement in astronomy: the orbit of each planet is an ellipse that has the sun at one focus
2. : a statement in astronomy: the radius vector from the sun to each planet generates equal orbital areas in equal times
3. : a statement in astronomy: the ratio of the square of the revolution period to the cube of the orbital major axis is the same for all the planets