day one

noun

variants often Day One
: 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.
Advertisement In New Jersey, Governor-Elect Mikie Sherrill has championed efforts to reduce utility costs for working families, pledging on day one to declare a formal State of Emergency on Utility Costs freezing rates for families across the state. Alanna McCargo, Time, 17 Nov. 2025 This means this new version is still more expensive than if customers bought the console on day one. PC Magazine, 12 Nov. 2025 Be thoughtful about bringing in talent that’s trained to get even the most complex AI projects done well and delivering value from day one. Kathleen Walch, Fortune, 11 Nov. 2025 Marcos showed me the Brazilian side of the falls on day one, followed by the Argentinian side the next day. Taylor McIntyre, Travel + Leisure, 5 Nov. 2025 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 Nov. 2025.

Last Updated: - Updated example sentences
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