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.
Our interns are a crucial part of our newsroom operation and are treated as professional, full-time employees from day one. Charlotte Observer, 12 Oct. 2025 The San Francisco Chronicle’s Mackenzie Chung Fegan abandoned anonymity on day one, and the New York Times’ dual critics Tejal Rao and Ligaya Mishan went as far as starring in several videos to announce their tenure at the paper. Sam Stone, Bon Appetit Magazine, 10 Oct. 2025 Advertisement Marine veterans were embedded from day one, advising during the writing process and consulting on set to adjust posture, protocol, and language. Jp Mangalindan, Time, 9 Oct. 2025 The team has operated that way since day one. Jesse Granger, New York Times, 9 Oct. 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 20 Oct. 2025.

Last Updated: - Updated example sentences
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