event horizon

noun

: the surface of a black hole : the boundary of a black hole beyond which nothing can escape from within it

Examples of event horizon in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Nothing can escape the black hole’s threshold, called the event horizon. — Jacopo Prisco, CNN Money, 16 June 2026 The gravity beneath the surface of a black hole, or the event horizon, is so strong that nothing can escape — not even light. — Adam Harrington, CBS News, 4 June 2026 Rather than photographing the black hole itself, the telescope captured glowing material orbiting just outside its event horizon. — Kaif Shaikh, Interesting Engineering, 29 June 2026 The last stop in space took us to just outside the event horizon of Sagittarius A*, the unimaginably enormous black hole at the center of the Milky Way. — Rob Pegoraro, ArsTechnica, 3 July 2026 See All Example Sentences for event horizon

Word History

First Known Use

1956, in the meaning defined above

Time Traveler
The first known use of event horizon was in 1956

Rhymes for event horizon

See All Rhymes for event horizon

Browse Nearby Words

even the score
event horizon
even though
See all Nearby Words

Cite this Entry

“Event horizon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/event%20horizon. Accessed 8 Jul. 2026.

Copy Citation
Last Updated: - Updated example sentences
Love words? Need even more definitions?

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

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of gambol

See Definitions and Examples »

Popular in Grammar & Usage

See More

Is that lie 'bald-faced' or 'bold-faced'?

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?

Commonly Misspelled Words

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)
See More

Popular in Wordplay

See More

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List

One-Word Oxymorons: Bittersweet, Spendthrift, and More

Ten Words Ending with a Silent ‘T’

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

Is that lie 'bald-faced' or 'bold-faced'?

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
hangman letters and game
Hangman Lightning Round Figure out which word fits in the blanks.
See All