thirty

American  

[thur-tee] / ˈθɜr ti /

noun

• thirties
  plural

1. a cardinal number, 10 times 3.

2. a symbol for this number, as 30 or XXX.

3. a set of this many persons or things.

4. Printing, Journalism. 30-dash.

5. thirties, the numbers, years, degrees, or the like, from 30 through 39, as in referring to numbered streets, indicating the years of a lifetime or of a century, or referring to degrees of temperature.

   He works in the East Thirties. She must be in her thirties. The temperature was in the thirties yesterday.

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adjective

1. amounting to 30 in number.

thirty British  

/ ˈθɜːtɪ /

noun

1. the cardinal number that is the product of ten and three See also number

2. a numeral, 30, XXX, etc, representing this number

3. (plural) the numbers 30–39, esp the 30th to the 39th year of a person's life or of a century

4. the amount or quantity that is three times as big as ten

5. something representing, represented by, or consisting of 30 units

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determiner

1. 1. amounting to thirty

      thirty trees

   2. ( as pronoun )

      thirty are broken

Usage

Spelling tips for 30 The word thirty (30) is hard to spell because it doesn’t simply combine the spelling of the base number (three) with the suffix -ty, as is done in other easy-to-remember spellings like sixty and seventy.  How to spell thirty: When three is combined with suffixes, it transforms from three (a cardinal number) to third (an ordinal number). Then, the d is dropped: thirteen (not thirdteen); thirty (not thirdty). Remember: there's no d in thirty.

Other Word Forms

Noun Inflected Forms

• thirties
  plural

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Etymology

Origin of thirty

before 900; Middle English thritty, Old English thrītig, equivalent to thrī three + -tig -ty ¹; cognate with Dutch dertig, German dreissig, Old Norse thrjātīu

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Example Sentences

See Examples For:

thirty thirties

It wants a chair and thirty quiet minutes.

From Salon ● Aug. 11, 2026

Wood outlined his recommendations in the weekly “Greed and Fear” strategy note he’s been sending to clients for thirty years.

From MarketWatch ● Jul. 10, 2026

The Nikkei 225 gained 38% as the Bank of Japan tightened rates, leading to the highest interest rates in over thirty years.

From Barron's ● Jun. 30, 2026

The co-founder of Netflix, Reed Hastings, is leaving the company, stepping down as chairman of the streaming platform that he set up nearly thirty years ago.

From BBC ● Apr. 16, 2026

We’d be more OK on time if she’d scraped her hair into a ponytail and skipped the makeup, but that’s a useless thought to have when we’re less than thirty minutes out from exam time.

From "Keeping Pace" by Laurie Morrison

She first picked up a brush as a married mother of three in her thirties, and only after her father’s death.

From Los Angeles Times ● Sep. 21, 2026

Though still considered one of the world's best-known feminist activists, Steinem came to advocacy rather late in life - in her thirties.

From BBC ● Sep. 3, 2026

Confirmed traffic through the strait fell to just 10 ships Monday, according to ship-tracking firm Kpler, compared with levels in the thirties and forties early last week.

From The Wall Street Journal ● Jul. 14, 2026

During his two days of detention on the boat, Bertel, who is in his thirties, also spoke of "three soldiers in a container".

From Barron's ● May 22, 2026

Ti Jean was a muscular man in his thirties, a local farmer’s son who had witnessed what Farmer had accomplished in the central plateau over the last twenty years.

From "Mountains Beyond Mountains" by Tracy Kidder and Michael French

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