diurnal

adjective

di·ur·nal | \ dī-ˈər-nᵊl

Definition of diurnal

(Entry 1 of 2)

1a : recurring every day diurnal tasks

b : having a daily cycle diurnal tides

2a : of, relating to, or occurring in the daytime the city's diurnal noises

b biology : active chiefly in the daytime diurnal animals

c botany : opening during the day and closing at night diurnal flowers

diurnal

noun

Definition of diurnal (Entry 2 of 2)

1 archaic : diary, daybook

2 : journal sense 1a

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Examples of diurnal in a Sentence

Adjective

a love as constant and certain as the diurnal tides

Noun

a microfilm containing a collection of diurnals published by 19th-century American abolitionists

Recent Examples on the Web: Adjective

Under the new law, which takes effect in 90 days, pet dealers are required to regularly groom animals to prevent matting and flea and tick infestations and provide animals with diurnal lighting cycles, which mimic natural, 24-hour light patterns. — USA TODAY, "Smokey Bear, tarantula trek, censoring Adam and Eve: News from around our 50 states," 9 Aug. 2019 Passive house systems work really well in climates with big diurnal temperature swings, like the desert. — New York Times, "Do Americans Need Air-Conditioning?," 3 July 2019 That diurnal cycle is linked to the giant impact by a fundamental law of physics, the conservation of angular momentum. — Simon J. Lock, Scientific American, "When Earth and the Moon Were One," 2 July 2019 These sorts of scenes seem to create a theater set across which Tillim’s subjects move, like characters enacting a diurnal purpose. — Carole Naggar, The New York Review of Books, "Framing Time: Guy Tillim’s African Street Photography," 25 May 2019 By analyzing coyote scat, scientists have linked this behavioral change to dietary shifts from diurnal to nocturnal prey, with implications for small mammal communities and for competition with other predators. — Kaitlyn Gaynor, CNN, "To avoid humans, more wildlife now work the night shift," 14 June 2018 That leaves her beachside club almost the entire day to entertain the diurnal, even if that’s the only trait some of her patrons have in common. — New York Times, "You Can’t Hurt Lindsay Lohan Now," 26 June 2018 Sun bears, for example, are typically diurnal and sun-loving creatures; in undisturbed areas less than 20% of their activity occurred at night. — Kaitlyn Gaynor, CNN, "To avoid humans, more wildlife now work the night shift," 14 June 2018 That’s the conclusion of a new study, which shows that a variety of previously diurnal animals such as foxes, deer, and boars have become nocturnal to avoid human activity out of fear. — Elizabeth Gamillo, Science | AAAS, "Human activity is causing more and more animals to embrace the night," 14 June 2018

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