day one

noun, often capitalized D&O

Definition of day one

: the first day or very beginning of something

Keep scrolling for more

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

Against Chelsea on day one, Rashford converted from penalty spot and later displayed great composure to finish calmly after latching onto a long through ball., "Why Ole Gunnar Solskjaer Is the Perfect Manager for Marcus Rashford & Anthony Martial," 23 Aug. 2019 Check out all the highlights Billboard caught on day one. Taylor Weatherby, Billboard, "Lollapalooza Day 1: The Chainsmokers Come Full Circle, Normani Holds Her Own & 9 More Best Moments," 2 Aug. 2019 The next president can draw ideas from it on day one. David Roberts, Vox, "The 4 best ideas from Jay Inslee’s new climate justice plan," 30 July 2019 Janelle Monae kickstarted the movement on day one by wearing Thom Browne’s irreverent separates and a playful red newsboy cap. Janelle Okwodu, Vogue, "All the Best Fashion From Wimbledon 2019," 11 July 2019 Kentucky left-handed pitcher Zack Thompson and Louisville first baseman Logan Wyatt were both picked on day one. Jon Hale, The Courier-Journal, "Morning Coffee: How did Kentucky schools perform in this year's MLB draft?," 4 June 2019 Each station timed the students for 30 minutes on day one and one hour on day two. Ramona Sentinel, "Students give standout performance at national SkillsUSA," 17 July 2019 Its inclusion in 13 Reasons Why, reportedly against the professional counsel of suicide prevention experts who consulted on the series throughout production on its first season, had made the show controversial from day one. Isaac Feldberg, Fortune, "Netflix Re-Edits Controversial ’13 Reasons Why’ Suicide Scene Two Years Later," 16 July 2019 But these moms put in the effort so their babies are as poisonous as possible from day one. National Geographic, "Bats regurgitate nectar for their babies—a new discovery," 12 July 2019

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.

See More

First Known Use of day one

1971, in the meaning defined above

Keep scrolling for more

Learn More about day one

Statistics for day one

Last Updated

27 Aug 2019

Look-up Popularity

Time Traveler for day one

The first known use of day one was in 1971

See more words from the same year

Keep scrolling for more

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).


one from the Upper Peninsula of Michigan

Get Word of the Day daily email!

Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Dictionary Devil

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!