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

see also:

once again once and for all once in a while

once

2 of 4

noun

: one single time : one time at least

Please be on time this once.

see also:

at 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.

Synonyms of once

Adverb

• formerly

Adjective

• former
• old
• other
• erstwhile
• past
• sometime
• late

Conjunction

• 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

More diverse voices, once overlooked in beauty, including Black women and other women of color, as well as the LGBTQ+ community, flourished during the era. —Taylor Ardrey, USA Today, 21 Feb. 2026

Spohr died after being shot once in the head during the burglary at the couple’s Homewood residence on the west shore of Lake Tahoe, the victims’ family has said. —Rosalio Ahumada, Sacbee.com, 21 Feb. 2026

Noun

Scrambling to find a district that fits, though sometimes unseemly, is commonplace for politicians of both major parties after the usual once-a-decade redistricting process. —Michael Smolens, San Diego Union-Tribune, 5 Dec. 2025

By 1982, the penny’s once-copper character had given way to cheaper zinc as metal prices climbed and its popularity with the public began to wane. —Marc Ramirez, USA Today, 12 Nov. 2025

Adjective

Bacevich’s 2020 book The Age of Illusions: How America Squandered Its Cold War Victory, was an early articulation of the once niche viewpoint that Fink lent support to on Tuesday. —Sasha Rogelberg, Fortune, 20 Jan. 2026

The once summer home became a residential dwelling once more. —Nandika Chatterjee, Time, 5 Nov. 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 above

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/more
• once bitten, twice shy
• once in a blue moon
• once in a lifetime
• once more
• 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