day one

noun

often capitalized D&O

: the first day or very beginning of something

Synonyms

• alpha
• baseline
• beginning
• birth
• commencement
• dawn
• genesis
• get-go
• git-go
• inception
• incipience
• incipiency
• kickoff
• launch
• morning
• nascence
• nascency
• onset
• outset
• start
• threshold

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

Culture, career growth, purpose and flexibility must be deliberately designed into the employee experience from day one. —Pete First, Forbes.com, 20 June 2025

Their casual design can lift you up for everyday wear with soft, flexible materials designed to feel broken in from day one. —Caley Sturgill, Southern Living, 20 June 2025

In particular, fans of Zack Snyder's DC films who don't approve of the DC Studios reboot have been voicing their disapproval since day one, with some going so far as to try to organize a review bombing campaign. —Michileen Martin, MSNBC Newsweek, 19 June 2025

Jeremiah, who had been coupled with Huda since day one, was paired with Iris. —Taylor Ardrey, USA Today, 18 June 2025

Word History

First Known Use

1971, in the meaning defined above

Rhymes for day one

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