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

Christian Louboutin is all suited up for day one of Paris Fashion Week on July 6. — Brendan Le, PEOPLE, 9 July 2026

The main criteria for deals is that the acquisition has pay their way from day one, Al Lamki said. — Ed Clowes, semafor.com, 8 July 2026

What the market now needs are products built on the right foundation from day one. — Ivan Kan, Forbes.com, 7 July 2026

Day One offers advocacy support as well as clinical and therapy services to support survivors, victims and their families, according to its website. — Katie Mulvaney, The Providence Journal, 3 July 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