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

But Tehran has flexed its military might in the Strait of Hormuz, a waterway that is crucial to international trade routes through which a fifth of the world’s total oil consumption passes. —Ellen Mitchell, The Hill, 17 Feb. 2026

More than two-fifths of working women have served as caregivers to people other than their children, according to a 2025 report from the Transamerica Center for Retirement Studies. —Daniel De Visé, USA Today, 16 Feb. 2026

The two cities accounted for one-fifth of the traffic to US government websites in the last three months. —Prashant Rao, semafor.com, 16 Feb. 2026

The mix skews intermediate (around 42 percent), with about one-fifth marked advanced, and a significant portion labeled beginner (36 percent)—though insiders joke the greens here ride more like blues. —Denny Lee, Travel + Leisure, 16 Feb. 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