day one

noun

variants often Day One

: the first day or very beginning of something

Synonyms of day one

• beginning
• start
• inception
• commencement
• alpha
• onset
• launch

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

Rhinerson said Tuma’s Little Fawn menu has been a success with diners from day one. —Pam Kragen, San Diego Union-Tribune, 4 Nov. 2025

Zhang said that his company has had to be globally focused from day one, given Australia’s relatively small market. —Leo Schwartz, Fortune, 3 Nov. 2025

This is going to be a battle from day one, with all three well-prepared to dominate college hoops from the opening tip. —Sam Vecenie, New York Times, 3 Nov. 2025

Keith Cox, currently President of MTVE Studios & Showtime and a champion of Yellowstone since day one, will continue to oversee our expansive lineup of shows from the Taylorverse and will report to me. —Rick Porter, HollywoodReporter, 30 Oct. 2025

Word History

First Known Use

1953, in the meaning defined above

Rhymes for day one

• begun
• grandson
• gudrun
• handgun
• homespun
• outdone
• outrun
• pashtun
• redone
• rerun
• shotgun
• someone