eighth

noun

ˈātth 

ˈāth

plural eighths ˈāt(th)s 

ˈāths

1

: one that is number eight in a series

the eighth of the month

see Table of Numbers

2

: one of eight equal parts of something

one eighth of a pie

an eighth of a pound

3

: eighth note

4

: octave

He contrasted himself with Elton John, who complained that his chubby hands could only reach an eighth, which was a hindrance to his piano technique (though clearly he overcame the problem).

—Susan Wyndham

eighth adjective or adverb

the eighth person in line

the country's eighth largest city

Examples of eighth in a Sentence

one eighth of the pie

An eighth of a pound is two ounces.

Recent Examples on the Web

The ballot wording Measure A will add five-eighths of a cent for five years to each dollar of taxable goods, pushing the total rate to 10% or more in most of Santa Clara County. —Daniel Borenstein, Mercury News, 9 Jan. 2026

In 2019, the cocaine cutoff for Michigan’s child welfare agency was 1 ng/ml — one-eighth of the federal level. —Lucas Waldron, ProPublica, 6 Jan. 2026

But the agency has about one-eighth the staff of the SEC, despite Kalshi alone receiving more than $2 billion in trades in a single week. —Bobby Allyn, NPR, 5 Jan. 2026

At just 80 cm (31 inches) tall and roughly one-eighth the weight of its full-size humanoids, the Q1 features full-body force control and crash-resistant Quasi-Direct Drive joints. —Jijo Malayil, Interesting Engineering, 1 Jan. 2026

Word History

First Known Use

1557, in the meaning defined at sense 2

Phrases Containing eighth

• eighth note
• eighth rest

Kids Definition

eighth

noun

ˈātth 

plural eighths ˈāt(th)s 

: one that is number eight in a series see number

eighth adjective or adverb