once

1 of 4

adverb

ˈwən(t)s 

1

: one time and no more

rode a horse only once

went skydiving once

2

: at any one time : under any circumstances : ever

didn't once thank me

3

: at some indefinite time in the past : formerly

was once a booming mining town

4

: by one degree of relationship

first cousin once removed

once

2 of 4

noun

: one single time : one time at least

Please be on time this once.

once

3 of 4

adjective

: that once was : former

… contributions to enrich the legal resources of the once province of Britain.

—J. N. Pomeroy

once

4 of 4

conjunction

: at the moment when : as soon as

Once she spoke, I recognized her.

Phrases

once and for all

1

: with finality : definitively

The team proved once and for all that they are the best.

2

: for the last time

I'm telling you once and for all that I'm not going.

once in a while

: now and then

spent most of their time at home, but went out once in a while

at once

1

: at the same time : simultaneously

2

: immediately

3

: both entry 2

at once funny and sad

Synonyms

Adverb

• erstwhile
• formerly
• onetime

Adjective

• erstwhile
• former
• late
• old
• onetime
• other
• past
• quondam
• sometime
• whilom

Conjunction

• as soon as
• immediately [chiefly British]
• instantly
• when

Examples of once in a Sentence

Adverb

I will repeat the question once.

The play was performed only once.

She didn't once thank me.

He didn't look at me once.

It was once done that way.

A river once flowed through this canyon.

It was once a booming mining town.

Their music was once very popular.

Noun

I have tried Indian food more than once.

Please be on time just this once.

For once you seem to know what I'm talking about.

Adjective

the once child star is now a lawyer in the entertainment industry

Conjunction

Once she spoke, I recognized her.

you should have stopped wrestling once you knew someone was getting hurt, not five minutes later

Recent Examples on the Web

Adverb

The news comes after the Federal Aviation Administration, which licenses commercial rocket launches, gave official approval Thursday, May 22 for SpaceX to launch Starship once again. —Eric Lagatta, USA Today, 25 May 2025

When Arielle was once at a company event with Justin, someone approached her for an introduction to him, and couldn’t contain their excitement. —David Hill, Rolling Stone, 24 May 2025

Noun

While the front-of-house was abuzz with celebrities vying to be noticed, the once dapper and demure designers in the mold of a Christian Dior or Hubert de Givenchy were now being replaced by upstarts like John Galliano and Alexander McQueen. —Ivan Shaw, Vogue, 18 June 2024

Here are some highlights of ready-to-wear collections Thursday: GIVENCHY GETS FEMININE The once-street and urban Matthew M. Williams uttered a word not often heard describing his designs: Elegant. —Thomas Adamson, ajc, 2 Mar. 2023

Adjective

You might be left with tiny scratches that make your once pristine appliances and surfaces look less than stellar. —Patricia Shannon, Better Homes & Gardens, 28 Apr. 2025

The price target increases come as industry giant BYD last week announced ultra-fast charging technology, on top of its launch in February of driver-assist systems for a range of its cars — signaling the once niche feature is going mainstream. —Evelyn Cheng, CNBC, 23 Mar. 2025

Word History

Etymology

Adverb, Noun, Adjective, and Conjunction

Middle English ones, from genitive of on one

First Known Use

Adverb

12th century, in the meaning defined at sense 1

Noun

13th century, in the meaning defined at sense 1

Adjective

1620, in the meaning defined above

Conjunction

1747, in the meaning defined above

Phrases Containing once

• at once
• every once in a while
• give (someone or something) a/the once-over
• once again
• once again/more
• once bitten, twice shy
• once in a blue moon
• once in a lifetime
• once or twice
• once-over
• once that
• once upon a time
• you're only young once

Rhymes for once

• bunce
• dunce

Kids Definition

once

1 of 3 adverb

ˈwən(t)s 

1

: one time only

will repeat the question once

2

: at any one time : ever

once you hesitate, it's too late

3

: at some time in the past : formerly

it was once done that way

4

: by one degree of relationship

cousin once removed

once

2 of 3 noun

: one single time

just this once

once

3 of 3 conjunction

: as soon as

once that is done, all will be well