Kepler's law

noun Kep·ler's law \ˈkeplə(r)z-\

Definition of Kepler's law

  1. 1 :  a statement in astronomy: the orbit of each planet is an ellipse that has the sun at one focus

  2. 2 :  a statement in astronomy: the radius vector from the sun to each planet generates equal orbital areas in equal times

  3. 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

Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Join MWU now and get access to America’s largest dictionary, with:

  • 300,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Origin and Etymology of kepler's law

after Johannes Kepler

Seen and Heard

What made you want to look up Kepler's law? Please tell us where you read or heard it (including the quote, if possible).


feeling or affected by lethargy

Get Word of the Day daily email!