periastron

noun
peri·​as·​tron | \ ¦perē¦astrən, -ˌsträn \
plural periastra\ -​strə \

Definition of periastron

: the point in the orbit of a star or other celestial body where it is nearest to the primary star with reference to which it is revolving the periastron of a comet — compare apastron

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!

History and Etymology for periastron

New Latin, from peri- + Greek astron star

Keep scrolling for more

Learn More about periastron

Statistics for periastron

Cite this Entry

“Periastron.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/periastron. Accessed 18 January 2020.

Comments on periastron

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

WORD OF THE DAY

experienced by way of someone else

Get Word of the Day daily email!

Test Your Vocabulary

The Eponym Quiz

  • rubens painting
  • Which is the best synonym of bowdlerize?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Add Diction

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

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