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

The mayor before that, Bill de Blasio, had pledged to eliminate the rides on day one of his administration but abandoned the crusade after heavy opposition from unions and a media blitz involving actor Liam Neeson. — Anthony Izaguirre, Los Angeles Times, 14 Oct. 2026

Australia was in strife at 124-6 on day one but his 190 turned the momentum. — ABC News, 13 Oct. 2026

On day one, about 90 percent of our customers shipped domestically only. — Arthur Zaczkiewicz, Footwear News, 13 Oct. 2026

Peter Chernin and Jesse Jacobs believed in Hello Sunshine from day one. — Jack Dunn, Variety, 13 Oct. 2026

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