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

To answer these questions effectively: • Entrepreneurs and technology developers should integrate automation and standardized protocols from day one, designing with scale in mind. —Yash Sinha, Forbes.com, 28 Mar. 2025

Wicked also shattered records for Universal as their biggest movie on PVOD in day one sales ($26M) and first week ($70M). —Anthony D'alessandro, Deadline, 28 Mar. 2025

Miller would slot into the Baltimore rotation from day one, while Honeycutt would be a huge addition to a depleted Dodgers farm system. —Paul Du Quenoy, MSNBC Newsweek, 27 Mar. 2025

Studios provide a compelling value proposition—offering founders a pre-assembled team, operational infrastructure and financial stability from day one. —Pierrick Bouffaron, Forbes, 25 Mar. 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