the fifth letter of the Greek alphabet (E, ε).
the consonant sound represented by this letter.
Mathematics. an arbitrarily small quantity, used to indicate that a given quantity is small, or close to zero.
First recorded in 1400–50; from Greek e psīlón “bare, simple e ” (as opposed to diphthongal spellings which in later Greek represented the same sound)
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Epsilon Indi Ab orbits about four times farther from its star than Jupiter does from the Sun.
From Science Daily • Apr. 22, 2026
Their next-door neighbors are three Delta Kappa Epsilon fraternity brothers developing AI that helps insurance companies sell more policies.
From The Wall Street Journal • Apr. 4, 2026
Named Epsilon Indi, the star is the smallest and coolest dwarf star yet observed with solar-like oscillations -- "starquakes" like those shown by the Sun.
From Science Daily • Mar. 26, 2024
Japan's recent space-related efforts have faced other setbacks, with the launch failure of the Epsilon small rocket in October 2022, followed by an engine explosion during a test last month.
From Reuters • Aug. 28, 2023
When Sasha came home for vacation, they proudly wore an Epsilon Theta sweatshirt.
From "The 57 Bus" by Dashka Slater
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
