fifth

noun

ˈfith  ˈfif(t)th 

ˈfift

plural fifths ˈfiths 

ˈfif(t)ths, 

ˈfif(t)s

1

: one that is number five in a series

Payment is due on the fifth of the month.

see Table of Numbers

2

: one of five equal parts of something

spent a fifth of their income on rent

3

a

: the musical interval embracing five diatonic degrees

b

: a tone at this interval

specifically : dominant sense 1

c

: the harmonic combination of two tones at this interval

4

: a unit of measure for liquor equal to one fifth of a U.S. gallon (0.757 liter)

5

the Fifth : the Fifth Amendment of the U.S. Constitution

also : the right accorded by the Fifth Amendment to refuse to testify against oneself see also plead the fifth, take the fifth

fifth adjective or adverb

the fifth annual food festival

She finished fifth in the race.

fifthly adverb

Fourthly, it takes a lot of concrete to make a nuclear power plant. Fifthly, there is no place to put the waste that is safe.

—Victor Odlivak

Examples of fifth in a Sentence

The bill is due on the fifth of each month.

She donated a fifth of her income to charity.

bought a fifth of whiskey

Recent Examples on the Web

The Middle East conflict prompted the Iranian closure of the Strait of Hormuz, a maritime trading route that facilitates the transport of about one-fifth of global oil supply. —Max Zahn, ABC News, 12 June 2026

The effective closure of the narrow waterway, which normally carries around a fifth of the world's oil supply, has led to global economic ramifications, with energy prices soaring and an uptick in inflation. —Elsa Ohlen, CNBC, 12 June 2026

Over a fifth of America’s population lives in the Midwest, with three of the country’s five fastest-growing metro areas located in the region, according to Census data. —Dobrina Zhekova, Travel + Leisure, 12 June 2026

But sentiment will likely remain in the dumps unless gas prices continue to fall meaningfully, likely requiring oil tankers to flow freely again through the Strait of Hormuz, a key chokepoint through which one-fifth of the world’s oil passes. —Bryan Mena, CNN Money, 12 June 2026

Word History

Etymology

Middle English fifte, fifthe, from Old English fīfta, from fīf five

First Known Use

1557, in the meaning defined at sense 2

Phrases Containing fifth

• fifth column
• fifth disease
• fifth wheel
• plead the fifth

Kids Definition

fifth

noun

ˈfith  ˈfif(t)th 

1

: one that is number five in a series see number

2

: the difference in pitch between the first tone and the fifth tone of a scale

fifth adjective or adverb

fifthly adverb