1
: one that is number four in a series
I was the fourth to arrive.
They arrive on the fourth. [=the fourth day of the month]
see Table of Numbers
2
: one of four equal parts of something : quarter entry 1
Cut the cake into fourths.
a fourth of the population
3
a
: a musical interval (see interval sense 2) embracing four tones of the diatonic scale
b
: a tone at this interval
specifically : subdominant sense 1
c
: the harmonic combination of two tones a fourth apart
4
: the fourth forward gear or speed of a motor vehicle
shifted into fourth
5
the Fourth : July 4 observed as a legal holiday in the U.S. in commemoration of the adoption of the Declaration of Independence in 1776 : fourth of july
watched fireworks on the Fourth

called also Independence Day

fourth adjective or adverb
the fourth edition of a book
the fourth tallest mountain
fourthly adverb
Fourthly, don't sing a whole opera through … —Mark Twain

Examples of fourth in a Sentence

cut the cake into fourths She drank a fourth of the bottle.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Families in the bottom one-fourth of income median net worth declined 6% while average net worth fell 4%. — Jeff Cox, CNBC, 9 Oct. 2026 More than three-fourths of respondents (76 percent) identified the relationship between shippers and transportation partners as the one most in need of closer collaboration to mitigate freight fraud. — Glenn Taylor, Footwear News, 8 Oct. 2026 Padres starter Walker Buehler yielded just three hits and a run, but manager Craig Stammen replaced him with Game 1 starter Robbie Ray after William Contreras’ leadoff single in the fourth. — ABC News, 8 Oct. 2026 Vilade, a 27-year-old getting extensive big league playing time this year with his sixth major league organization, hit an opposite-field, 340-foot drive into the right-field short porch in the fourth. — CBS News, 8 Oct. 2026 See All Example Sentences for fourth

Word History

Etymology

see four

First Known Use

1594, in the meaning defined at sense 2

Time Traveler
The first known use of fourth was in 1594

Cite this Entry

“Fourth.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fourth. Accessed 14 Oct. 2026.

Kids Definition

1
: one that is number four in a series see number
2
: the difference in pitch between the first tone and the fourth tone of a scale
fourth adjective or adverb
fourthly adverb

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