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

Waging drone strikes on tankers and issuing threats of laying sea mines, Iran has effectively shut down the narrow body of water through which a fifth of the world’s supply of oil and natural gas flows. —Sudarsan Raghavan, New Yorker, 25 Mar. 2026

Roughly one-fifth of global oil supply passes through the strait, but attacks on ships have stopped nearly all tanker traffic. —Arkansas Online, 25 Mar. 2026

That’s less than one-fifth of what prosecutors were seeking. —Morgan Lee, Los Angeles Times, 25 Mar. 2026

If this exercise were done five years ago, prior to the 2021 season, at least four-fifths of this year’s rotation wouldn’t have been in the organization. —Shawn McFarland, Dallas Morning News, 24 Mar. 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