[ ep-suh-lon, -luh n or, esp. British, ep-sahy-luh n ]
/ ˈɛp səˌlɒn, -lən or, esp. British, ɛpˈsaɪ lən /


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.

Origin of epsilon

< Greek è psīlón bare, simple e (as opposed to diphthongal spellings which in later Gk represented the same sound)
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for epsilon

British Dictionary definitions for epsilon (1 of 2)

/ (ˈɛpsɪˌlɒn, ɛpˈsaɪlən) /


the fifth letter of the Greek alphabet (Ε, ε), a short vowel, transliterated as e

Word Origin for epsilon

Greek e psilon, literally: simple e

British Dictionary definitions for epsilon (2 of 2)

/ (ˈɛpsɪˌlɒn, ɛpˈsaɪlən) /


(foll by the genitive case of a specified constellation) the fifth brightest star in a constellationEpsilon Aurigae
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for epsilon

[ ĕpsə-lŏn′, -lən ]


The fifth letter of the Greek alphabet.
The fifth in a series.


Of or relating to the fifth member of a particular ordered set.
Relating to or characterizing a polypeptide chain that is one of five types of heavy chains present in immunoglobins.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.