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.
Design for downside risk from day one. Kat Marie Alvarez, Forbes.com, 26 June 2026 What can state workers expect on day one? Kat Tran, Sacbee.com, 26 June 2026 Since day one, music has always been my artistic vehicle to amplify creativity, connection, community, collaboration, and maximum amplification of human emotion. Jem Aswad, Variety, 25 June 2026 Oceania Cruises Recently converted to an adults-only luxury cruise line, Oceania Cruises ensures single voyagers feel at home on day one. Janice Wald Henderson, Condé Nast Traveler, 24 June 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 29 Jun. 2026.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster