day one

noun

often capitalized D&O
: the first day or very beginning of something

Examples of day one in a Sentence

We've known this about the project since Day One. since day one of this project, we've always insisted that we would create the best product possible without any consideration of cost
Recent Examples on the Web Jameela, the first baby gorilla born by Cesarean section at the Fort Worth Zoo, has been under the constant care of Holmes and a multitude of other zoo staff since day one. Harriet Ramos, Fort Worth Star-Telegram, 22 Mar. 2024 Adobe Express users won’t see their projects from the existing mobile app in the new beta app on day one. Jess Weatherbed, The Verge, 7 Mar. 2024 Closing this gap is arguably the largest public good for which the requisite financing needs to be incorporated within AfCFTA from day one. Harry G. Broadman, Forbes, 29 Feb. 2024 The 2024 season officially kicked off today with the Bahrain Grand Prix, and, for day one of their practice session, drivers showed up to the paddock dressed to impress. Irene Kim, Vogue, 28 Feb. 2024 That’s probably a third of what GTA 6 will sell on day one next year. Paul Tassi, Forbes, 28 Mar. 2024 On Monday, Drake took to Instagram to salute his day one ally Lil Wayne, while changing his profile picture to the Young Money boss. Andre Gee, Rolling Stone, 25 Mar. 2024 And seeing as Day One picks should really be playing on day one of the season, that’s a huge win. 63. Dieter Kurtenbach, The Mercury News, 18 Mar. 2024 Her manicure lasted almost seven days with one popping off and some minor chips, but otherwise looked the same as day one. Kate Watson, Peoplemag, 16 Mar. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'day one.' 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

1971, in the meaning defined above

Time Traveler
The first known use of day one was in 1971

Dictionary Entries Near day one

Cite this Entry

“Day one.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/day%20one. Accessed 19 Apr. 2024.

Last Updated: - Updated example sentences
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