solar day


: the interval between transits of the apparent or mean sun across the meridian at any place

Examples of solar day in a Sentence

Recent Examples on the Web If a person doesn’t get enough exposure to daytime light, perhaps due to long hours at school or the office, misalignment between the various clocks and the solar day can set off cascading effects. Carla Delgado, Discover Magazine, 29 Mar. 2022 When deprived of information from the outside world, the sleep-wake cycle usually lagged slightly slower than the solar day, with a period averaging around 25 hours. Jo Marchant, Wired, 1 Sep. 2020 Near the December solstice, each solar day runs about 24 hours and 30 seconds long. Justin Grieser, Anchorage Daily News, 21 Dec. 2022 The first division of the day’s 24 hours (known in Latin as partes minutae primae) gave them the length of the minute, which was one-1,440th of an average solar day. New York Times, 25 Apr. 2022 One solar day—a full day-night cycle—takes 176 Earth days. Jennifer Leman, Popular Mechanics, 9 Nov. 2019 It’s eleven-thirty at night according to my watch, but this far south the hour of the solar day is of no help in trying to understand the situation we’re in here, or our work rhythms. Barry Lopez, Harper's magazine, 10 Jan. 2019 In the 1980s and 1990s, the three scientists who received the award figured out how genetic time counters in cells aligned biological function to the 24-hour solar day. Jacqueline Detwiler, Popular Mechanics, 26 Dec. 2018 The length of a solar day, measured by the time between the sun’s passage of any particular point in the sky, is rarely 24 hours precisely. Scott Dance,, 13 June 2018

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'solar day.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1751, in the meaning defined above

Time Traveler
The first known use of solar day was in 1751

Dictionary Entries Near solar day

Cite this Entry

“Solar day.” Dictionary, Merriam-Webster, Accessed 25 Jul. 2024.

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