quartile

American  

[kwawr-tahyl, -til] / ˈkwɔr taɪl, -tɪl /

noun

1. Statistics. (in a frequency distribution) one of the values of a variable that divides the distribution of the variable into four groups having equal frequencies.

2. Astrology. a quartile aspect.

---

adjective

1. Astrology. of or relating to the aspect of two heavenly bodies when their longitudes differ by 90°.

quartile British  

/ ˈkwɔːtaɪl /

noun

1. statistics one of three actual or notional values of a variable dividing its distribution into four groups with equal frequencies

---

adjective

1. statistics denoting or relating to a quartile

2. astrology denoting an aspect of two heavenly bodies when their longitudes differ by 90°

3. a quarter part of a distribution

Etymology

Origin of quartile

1500–10; < Medieval Latin quartīlis, equivalent to Latin quart ( us ) fourth + -īlis -ile

Explanation

When statisticians divide things into four equal parts, any one of those parts is called a quartile. You might, for example, hear about a successful school that's in the upper quartile of state test scores. People studying information about how people live — how much money they make, how healthy they are, how much they travel, what their ages are, what TV shows they watch — often separate them into groups for comparison. It's sometimes easier to examine statistics and information when it's divided into quartiles, or fourths. The original use of the word quartile was in astronomy, to mean "ninety degrees apart," from the Latin root word quartus, "fourth."

Example Sentences

Notice that the stock market’s average subsequent return in the lowest quartile is higher than for either the second or third quartiles.

From MarketWatch • Mar. 13, 2026

The pro forma return on assets is 1.33%, in the top quartile of their peer group.

From Barron's • Jan. 23, 2026

At funds worth $10 billion or more, principals in the top pay quartile made at least $955,000 in base and bonus in 2023, according to an annual survey by recruiter Heidrick & Struggles.

From The Wall Street Journal • Nov. 20, 2025

"If you're already very active or in that top quartile, an extra hour's walk may not make much difference as you've, in a sense, already 'maxxed out' your benefit," he said.

From Science Daily • Nov. 26, 2024

Adj. four; quaternary, quaternal†; quadratic; quartile; tetract†, tetractic†, tetractinal†; tetrad, tetragonal; square, quadrate.

From Roget's Thesaurus of English Words and Phrases by Roget, Peter Mark