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
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.
From day one, gather as much feedback as possible; that’s how a good product becomes truly great. Rolling Stone Culture Council, Rolling Stone, 23 Sep. 2025 Nonprofits have also been central since day one. Luciana Perez Uribe Guinassi, Charlotte Observer, 22 Sep. 2025 Apple's commitment to continue providing manuals for DIY repairs from day one is also a big plus, according to iFixit. PC Magazine, 22 Sep. 2025 And they were promised in the last election that their costs were going to go down, that inflation was going to go away on day one. Jason Lemon, MSNBC Newsweek, 21 Sep. 2025 See All Example Sentences for day one

Word History

First Known Use

1971, in the meaning defined above

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

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Cite this Entry

“Day one.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/day%20one. Accessed 30 Sep. 2025.

Last Updated: - Updated example sentences
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