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

Holding a Capital Markets Day in Florence, Gucci’s home city, was on his mind since day one. —Laure Guilbault, Vogue, 16 Apr. 2026

Another Buckeye that will be fighting the positional value rhetoric on draft night, Sonny Styles could be a day one off-ball linebacker in the Christian Parker defensive scheme while also serving as the lead communicator and wearing the green dot on his helmet as a rookie. —Nick Harris april 16, Fort Worth Star-Telegram, 16 Apr. 2026

Adjusting your timer schedule now — rather than reacting mid-July — means your lawn gets consistent coverage from day one of the hot season. —Lauren Jarvis-Gibson, Charlotte Observer, 15 Apr. 2026

Our fight from day one has never been to hold the tribe down. —Ashley Sharp, CBS News, 15 Apr. 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