noc·​tur·​nal | \näk-ˈtər-nᵊl \

Definition of nocturnal 

1 : of, relating to, or occurring in the night a nocturnal journey nocturnal activities

2 : active at night a nocturnal predator nocturnal insects, such as mosquitoes

Keep scrolling for more

Other Words from nocturnal

nocturnally \ -​nᵊl-​ē \ adverb

Synonyms & Antonyms for nocturnal


night, nightly, nighttime


daily, diurnal

Visit the Thesaurus for More 

Examples of nocturnal in a Sentence

he bought a new telescope so he could pursue his favorite nocturnal hobby of astronomy

Recent Examples on the Web

The northern madtom is nocturnal and avoids shallow waters during the day. Michigan Wildlife Council, Detroit Free Press, "Polishing a gem: Plan aims for St. Clair-Detroit River system improvements," 10 July 2018 Not all animals are willing or able to just switch to a nocturnal lifestyle around people. Kaitlyn Gaynor, CNN, "To avoid humans, more wildlife now work the night shift," 14 June 2018 Why Attract Owls The haunting, magical sound of an evening owl call isn't the only benefit of attracting these nocturnal creatures to your land. Leah Zerbe, Good Housekeeping, "How To Attract Owls To Your Backyard," 14 Aug. 2015 Renna said mice are nocturnal, have poor vision and use their nose and whiskers to get around. Brittany Nader,, "University of Akron biology professor, team of scientists make breakthrough discovery on vision," 17 Jan. 2018 Largely nocturnal, mudpuppies are found under the cover of rocks and logs or other suitable structures. Michigan Wildlife Council, Detroit Free Press, "Polishing a gem: Plan aims for St. Clair-Detroit River system improvements," 10 July 2018 The idea that the Moon might have a relevance to life beyond providing nocturnal illumination was not new. The Economist, "Empty sky, empty Earth?," 5 July 2018 New York lawsuit seeks to dissolve Trump foundation. *More animals becoming nocturnal to avoid people. Chicago Tribune Staff,, "Morning Spin: Emanuel calls Chicago flag he gave Musk 'slightly better' than the Boring hat he received in return," 15 June 2018 Tour by van into sections of the forest where crepuscular and nocturnal creatures are most active. The Courier-Journal, "75+ fun things, including Halloween creeps, for week of Sept. 21-27," 20 Sep. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'nocturnal.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of nocturnal

15th century, in the meaning defined at sense 1

History and Etymology for nocturnal

Middle English, borrowed from Anglo-French & Late Latin; Anglo-French nocturnel, borrowed from Late Latin nocturnālis "for night use," from Latin nocturnus "of or occurring at night" (from noct-, nox night entry 1 + -urnus, temporal suffix, as in diurnus "of the day") + -ālis -al entry 1 — more at journal

Keep scrolling for more

Learn More about nocturnal

Dictionary Entries near nocturnal








Statistics for nocturnal

Last Updated

8 Nov 2018

Look-up Popularity

Time Traveler for nocturnal

The first known use of nocturnal was in the 15th century

See more words from the same century

Keep scrolling for more

More Definitions for nocturnal



English Language Learners Definition of nocturnal

: active mainly during the night

: happening at night


noc·​tur·​nal | \näk-ˈtər-nᵊl \

Kids Definition of nocturnal

1 : happening at night a nocturnal journey

2 : active at night nocturnal insects


noc·​tur·​nal | \näk-ˈtərn-ᵊl \

Medical Definition of nocturnal 

1 : of, relating to, or occurring at night nocturnal myoclonus

2 : characterized by nocturnal activity a nocturnal form of filariasis

Keep scrolling for more

Comments on nocturnal

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


playful or foolish behavior

Get Word of the Day daily email!

Test Your Vocabulary

Autumn Words of the Day 2018

  • a-top-down-image-of-road-through-an-autumn-forest
  • Which is a synonym of fugacious?
Spell It

Can you spell these 10 commonly misspelled words?


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


Love words? Need even more definitions?

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