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

Since its introduction, fifteen dissertations and final theses at Freie Universität have focused on the topic, along with seven additional dissertations completed by researchers in other countries.

From Science Daily • Jan. 7, 2026

“By early childhood most high-income nations vaccinate against roughly a dozen to fifteen serious pathogens,” the group said.

From Barron's • Jan. 5, 2026

Ten, fifteen, or twenty at a time would clutch at the tape, as it streamed out with its endless lines of quotations,” Miller wrote in the Chicago Tribune of Oct.

From The Wall Street Journal • Sep. 28, 2025

During his first days at Mount St. Helens, Swanson had flown to Goat Rocks and Sugar Bowl, another feature on the mountain about fifteen hundred feet below Goat Rocks.

From "Mountain of Fire" by Rebecca E. F. Barone