number one

noun

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

Keep scrolling for more

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

So is that priority number one — data privacy, data transparency? Makena Kelly, The Verge, "Silicon Valley’s Rep. Ro Khanna talks tech regulation on The Vergecast," 27 Nov. 2018 High number one: Sipping good Italian espresso on an upper deck as the boat glides through the Philippine region of Coron, passing Listerine-blue bays dotted with traditional bangka boats, with their double outriggers. Christopher Bagley, Condé Nast Traveler, "Sailing the South China Sea Is the Best Way to See Southeast Asia," 15 Nov. 2018 The number one way to prevent free radical damage to our skin is to wear broad-spectrum sunscreen every day, which protects cells from the negative effects of UVA and UVB rays. Jenn Sinrich, SELF, "The Best Antioxidants for Skin, According to Dermatologists," 8 Nov. 2018 Rule number one? Resist the urge to overcomplicate things. Andrew Skurka, Outside Online, "How to Pack for a Hike," 21 May 2018 For year-round pollution, Fairbanks, Alaska, beats out Californian cities to rank number one—an increase from last year’s number 17 spot. Julissa Treviño, Smithsonian, "These Are the Cities With the Worst Air Pollution," 24 Apr. 2018 The Dutchman, who has been ranked number one by DJ Mag five times, will play at King Abdullah Economic City on June 17 in what is seen as the latest sign that restrictions on entertainment in the Islamic kingdom are being eased, Arab News reported. Brendan Cole, Newsweek, "Dj Armin Van Buuren to Play at Saudi Arabia’s First Rave in Latest Sign Islamic Kingdom is Easing Restrictions," 21 Mar. 2018 Amazon did the obvious thing here: the old Dot sounded like crap, and the number one thing smart speakers are used for is to listen to music, so improving the sound quality was the right move. Dan Seifert, The Verge, "Amazon Echo Dot (3rd gen) review: better looks, better sound, same price," 12 Oct. 2018 Yet while London's Dandelyan was crowned number one, the spotlight shone firmly on Asia. Mark Ellwood, Condé Nast Traveler, "This Is Officially the Best Bar in the World," 4 Oct. 2018

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.

See More

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

Keep scrolling for more

Learn More about number one

Share number one

Statistics for number one

Look-up Popularity

Time Traveler for number one

The first known use of number one was circa 1705

See more words from the same year

Keep scrolling for more

More Definitions for number one

number one

noun

English Language Learners Definition of number one

 (Entry 1 of 2)

: a person, thing, or position that is highest in rank : the most important person or thing in a group of people or things

: the most successful person or thing in a group of people or things

: your own happiness, health, or success

number one

adjective

English Language Learners Definition of number one (Entry 2 of 2)

: highest in rank or importance

More from Merriam-Webster on number one

Thesaurus: All synonyms and antonyms for number one

Comments on number one

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

WORD OF THE DAY

the figure or shape of a crescent moon

Get Word of the Day daily email!

Test Your Vocabulary

Late Autumn 2018 Words of the Day Quiz

  • frosted-autumn-leaves
  • Which is a synonym of yahoo?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
SCRABBLE® Sprint

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

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!