fifteen

American  

[fif-teen] / ˈfɪfˈtin /

noun

1. a cardinal number, ten plus five.

2. a symbol for this number, as 15 or XV.

3. a set of this many persons or things.

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adjective

1. amounting to 15 in number.

fifteen ¹ British  

/ ˈfɪfˈtiːn /

noun

1. the cardinal number that is the sum of ten and five

2. a numeral, 15, XV, etc, representing this number

3. something represented by, representing, or consisting of 15 units

4. a rugby union football team

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determiner

1. 1. amounting to fifteen

      fifteen jokes

   2. ( as pronoun )

      fifteen of us danced

Fifteen ² British  

/ ˈfɪfˈtiːn /

noun

1. history the Jacobite rising of 1715

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Usage

Spelling tips for fifteen The word fifteen is hard to spell because it doesn’t simply combine the spelling of the base number, five, with the suffix -teen, as is done in other easy-to-remember spellings like fourteen and sixteen.  How to spell fifteen: When five is combined with suffixes, the ve is turned into an f: fifteen (not fiveteen), fifty (not fivety), and fifth (not fiveth). Remember: there’s no v in fifteen.

Etymology

Origin of fifteen

before 900; Middle English, Old English fiftene. See five, -teen

Example Sentences

The last mayoral race began shaping up in 2021, when former City Councilmember Joe Buscaino announced he was running about fifteen months before election day.

From Los Angeles Times • Feb. 5, 2026

Even though the planets are five to ten times larger than Earth, their masses are only five to fifteen times greater.

From Science Daily • Jan. 31, 2026

Lake Balaton in the west of the country is currently frozen -- a relatively rare phenomenon seen about once every ten to fifteen years.

From Barron's • Jan. 13, 2026

The boy was fifteen, skinny, almost malnourished, so that the hip bones and coccyx stood out sharply.

From The Wall Street Journal • Nov. 11, 2025

We finish the whole thing in like fifteen minutes.

From "Wayward Creatures" by Dayna Lorentz