epsilon

American  

[ep-suh-lon, -luhn, ep-sahy-luhn] / ˈɛp səˌlɒn, -lən, ɛpˈsaɪ lən /

noun

1. the fifth letter of the Greek alphabet (E, ε).

2. the consonant sound represented by this letter.

3. Mathematics. an arbitrarily small quantity, used to indicate that a given quantity is small, or close to zero.

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Epsilon ¹ British  

/ ˈɛpsɪˌlɒn, ɛpˈsaɪlən /

noun

1. (foll by the genitive case of a specified constellation) the fifth brightest star in a constellation

   Epsilon Aurigae

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epsilon ² British  

/ ˈɛpsɪˌlɒn, ɛpˈsaɪlən /

noun

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

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Etymology

Origin of epsilon

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)

Example Sentences

For the three stars with detected astrospheres, named 70 Ophiuchi, epsilon Eridani, and 61 Cygni, the researchers estimated their mass loss rates to be 66.5±11.1, 15.6±4.4, and 9.6±4.1 times the solar mass loss rate, respectively.

From Science Daily • Apr. 12, 2024

Last, one of the benefits of differential privacy is that specifications of the algorithms used, like epsilon, can be made public.

From Slate • Aug. 12, 2021

A few others made the rogue’s gallery of variants: gamma, beta, epsilon.

From Washington Post • Aug. 8, 2021

Another delta mutation — also found in kappa and epsilon — is called L452R.

From Salon • Jul. 29, 2021

There were five city quarters, designated by the Greek letters alpha through epsilon.

From "Circumference" by Nicholas Nicastro