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

For more than two decades, the award-winning brand has stayed true to its mission, delivering pro-level formulas (that have been cruelty-free since day one) anyone and everyone who has a love for makeup could afford. —Jackie Fields, Peoplemag, 17 May 2024

That is what this case has been about from day one. ... —Tess Riski, Miami Herald, 13 May 2024

Word History

First Known Use

1971, in the meaning defined above