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

When those memories are designed to last for years, privacy becomes part of the buying decision from day one. — Kurt Knutsson, FOXNews.com, 5 Sep. 2026

On day one in 2026, charter schools had 85,473 students enrolled and 79,633 students in attendance, down from 86,913 enrolled and 81,207 in attendance the prior academic year. — Sarah Perkel, USA Today, 2 Sep. 2026

September is living up to its infamous reputation , at least on day one. — Fred Imbert, CNBC, 1 Sep. 2026

Being ready to consume those APIs on day one is a huge opportunity. — Oleg Nesterov, Forbes.com, 1 Sep. 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