SINCE 1828
dictionary
thesaurus

number one

noun
Save Word

Definition of number one

 (Entry 1 of 2)

1 : one's own interests or welfare : oneself looking out for number one —often written No. 1
2 : one that is first in rank, importance, or influence —often written No. 1

number one

adjective

Definition of number one (Entry 2 of 2)

1 : first in rank, importance, or influence : foremost cancer is the country's number one killer —often written No. 1
2 : of highest or of high quality
Synonyms & Antonyms More Example Sentences Learn More About number one

Examples of number one in a Sentence

Noun Who's number one in this office? Getting the car fixed is number one on my list of priorities. I'll tell you why we can't go on a vacation: number one, we can't afford it, and number two, we'll miss my sister's party. Her movie is currently number one at the box office. When the goal was scored, the fans started to chant, “We're number one, we're number one.” I've been taking care of other people for too long. It's time for me to take care of number one. Adjective The book is the company's number one seller. Rule number one is don't get caught! He's public enemy number one: the nation's most wanted criminal. See More
Recent Examples on the Web: Adjective Within hours of its debut Friday, Un Verano Sin Ti shot to number one on Spotify and Apple Music. — Bianca Betancourt, Harper's BAZAAR, 9 May 2022 The number one source of the best hires is employee referrals. — Quora, Forbes, 6 May 2022 The arts alliance boasts that Dreamscapes is Salt Lake County’s number one partner in recycling. — Palak Jayswal, The Salt Lake Tribune, 2 May 2022 The trial had heard details of Becker’s career and how the former world number one, who won the Wimbledon championship three times, lost his fortune following his retirement. — NBC News, 29 Apr. 2022 Meredith Blake is by and large number one, but Lisa Luder has her moments. — Keaton Bell, Vogue, 27 Apr. 2022 Brian kemp has been made public enemy number one by Donald Trump. — ABC News, 24 Apr. 2022 Several years ago, the Federal Trade Commission identified the area of greenwashing and green products as the number one source of consumer misinformation. — Joan Meiners, The Arizona Republic, 20 Apr. 2022 In Wyoming, the primary challenger to Congresswoman Liz Cheney—seemingly Trump’s number one target to remove from office this cycle—is using National Public Affairs LLC, a firm made up of the top advisers of Trump’s erstwhile presidential campaign. — Daniel Strauss, The New Republic, 12 Apr. 2022 See More

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

First Known Use of number one

Noun

circa 1705, in the meaning defined at sense 1

Adjective

1839, in the meaning defined at sense 1

Learn More About number one

Time Traveler for number one

Time Traveler

The first known use of number one was circa 1705

See more words from the same year

Dictionary Entries Near number one

number nine iron

number one

number one iron

See More Nearby Entries 

Statistics for number one

Cite this Entry

“Number one.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/number%20one. Accessed 16 May. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

WORD OF THE DAY

epithet

Listen to the pronunciation of epithet

See Definitions and Examples »

Test Your Vocabulary

Name That Color

  • a light greenish blue color
  • Name that color:
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

TAKE THE QUIZ
Love words? Need even more definitions?

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

Words at Play
Ask the Editors
Word Games