astronomical twilight

noun

: the period after sunset or before sunrise ending or beginning when the sun is about 18 degrees below the horizon

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 astronomical twilight

astronomical triangle

astronomical twilight

astronomical unit

See More Nearby Entries 

Cite this Entry

“Astronomical twilight.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/astronomical%20twilight. Accessed 27 Mar. 2023.

Copy Citation

Share

Love words? Need even more definitions?

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

Word of the Day

Listen to the pronunciation of disparate

See Definitions and Examples »

Test Your Vocabulary

Challenging Standardized Test Words, Vol. 2

  • a pencil broken in half on top of a test answer sheet
  • The business’s new computer system proved not to be a panacea.
Spell It

Hear a word and type it out. How many can you get right?

TAKE THE QUIZ
Solve today's spelling word game by finding as many words as you can with using just 7 letters. Longer words score more points.

Can you make 12 words with 7 letters?

PLAY
Words at Play
Ask the Editors
Word Games