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

In practice, explainability needs to be designed into the system from day one. — Sandeep Shivam, Forbes.com, 10 Aug. 2026

Standing in their way of another victorious night following the Freedom’s day one win over the Missouri Thunder was the New York Mavericks. — Ava Dicecca, Sun Sentinel, 9 Aug. 2026

Meanwhile, Whitney and Justin Rose are the first couple who’s been on the show since day one to break up. — Jason P. Frank, Vulture, 6 Aug. 2026

Visit the school building or playground so the environment feels familiar on day one. — Ashley Lynch, Sacbee.com, 6 Aug. 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