day one

noun

variants often Day One
Synonyms of day onenext
: 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
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.
The Architects do everything else — find the money, develop the package, enroll the best possible team, find distribution, and market the film every single day from day one to reach as many people as possible. Daren Smith, IndieWire, 18 Mar. 2026 From day one, Rosie’s has been a popular stopover for those heading to Lake Travis and the Hill Country. Michael Barnes, Austin American Statesman, 17 Mar. 2026 Embed governance from day one, not as afterthought compliance. K. H. Koehler, AZCentral.com, 13 Mar. 2026 Bri even said she's been all in on Connor since day one and was never torn between him or Chris. Randall Colburn, Entertainment Weekly, 12 Mar. 2026 See All Example Sentences for day one

Word History

First Known Use

1953, in the meaning defined above

Time Traveler
The first known use of day one was in 1953

Browse Nearby Words

Cite this Entry

“Day one.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/day%20one. Accessed 20 Mar. 2026.

Last Updated: - Updated example sentences
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