day one

noun, often capitalized D&O

Definition of day one 

: the first day or very beginning of something

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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

Between seeing his first feature film greenlighted and day one of production, Bo Burnham had eight months to figure out how to direct. Mia Galuppo, The Hollywood Reporter, "How Bo Burnham Went From YouTube to Stand-Up to Directorial Breakout 'Eighth Grade'," 26 June 2018 Today marked day one of Royal Ascot 2018, a five-day horse race attended by members of the royal family—including the Queen—every year. Julie Kosin, Harper's BAZAAR, "The Duchess of Cambridge Skipped Today's Royal Ascot for an Understandable Reason," 19 June 2018 Freshmen don’t come in day one with the type of abilities and attributes that Jacoby showed. Shawn Mcfarland,, "Impressive Freshman Year From Glastonbury's Ronan Jacoby Helps Wesleyan To National Championship," 24 May 2018 But on January 20th of last year, Donald Trump assumed the presidency of the United States, and since day one – when references to LGBTQ people were purged from the White House website – the LGBTQ community was forced to face a new world order. Sarah Kate Ellis, Time, "President Trump Is Trying to Erase the LGBTQ Community," 16 Jan. 2018 Compounding the challenge: traders can short-sell the stock from day one and Xiaomi won’t be considered for inclusion in benchmark MSCI gauges. Ian Mount, Fortune, "Chinese Smartphone Maker Xiaomi’s Monster IPO Flops on Its First Day of Trading," 9 July 2018 Thankfully, everything else that came with the IIsi worked great from day one, needing no repairs whatsoever. Chris Wilkinson, Ars Technica, "1990, meet 2018: How far does 20MHz of Macintosh IIsi power go today?," 1 July 2018 Interior Secretary Ryan Zinke came into office moving to expand public hunting ground from day one and issued directives last year aimed at fishing and hunting guidelines from the department. Eli Watkins, CNN, "Interior proposes allowing Alaskan hunters to bait bears, kill wolf pups," 22 May 2018 The City of Texas City has supported us from day one and their contributions have increased as the show has grown. Heidi Van Horne, Houston Chronicle, "Texas City hosts Lone Star Deluxe Hot Rod and Music Festival this weekend," 28 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'day one.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of day one

1971, in the meaning defined above

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Statistics for day one

Last Updated

5 Nov 2018

Look-up Popularity

Time Traveler for day one

The first known use of day one was in 1971

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More Definitions for day one

day one


English Language Learners Definition of day one

: the first day or very beginning of something

More from Merriam-Webster on day one

Thesaurus: All synonyms and antonyms for day one

Comments on day one

What made you want to look up day one? Please tell us where you read or heard it (including the quote, if possible).


something that serves to warn or remind

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