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.
Guardian Litigation Group’s Litigation-First Strategy Guardian Litigation Group offers a unique service: legal representation from day one, at no additional cost to clients seeking debt settlement services. Jason Phillips, USA Today, 26 July 2025 Collin Morikawa of the United States plays an approach shot on the first hole during day one of The 153rd Open Championship at Royal Portrush Golf Club on July 17, 2025, in Portrush, Northern Ireland. Joe Kozlowski, MSNBC Newsweek, 25 July 2025 Meanwhile, India will gain tariff-free access on 99% of imports from day one of the agreement. Ganesh Rao, CNBC, 25 July 2025 The emotional distance was clear from day one, even on the woman’s wedding day. Ashley Vega, People.com, 24 July 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

Browse Nearby Words

Cite this Entry

“Day one.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/day%20one. Accessed 29 Jul. 2025.

Last Updated: - Updated example sentences
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