Iapetus

noun

Iap·​e·​tus ī-ˈa-pə-təs How to pronounce Iapetus (audio)
astronomy
: the third largest satellite of Saturn with a diameter of approximately 890 miles (1440 km)
Ever since J.D. Cassini discovered the object in 1671, astronomers have puzzled over why Iapetus' leading hemisphere (facing forward along its orbit) is dark and its trailing one bright.J. Kelly Beatty, Sky & Telescope, November 1983

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.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Dictionary Entries Near Iapetus

Cite this Entry

“Iapetus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Iapetus. Accessed 22 Nov. 2024.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!