upsilon

American  

[yoop-suh-lon, -luhn, uhp-, yoop-sahy-luhn] / ˈyup səˌlɒn, -lən, ˈʌp-, yupˈsaɪ lən /

noun

1. the 20th letter of the Greek alphabet (Υ, υ).

2. the vowel sound represented by this letter.

3. Also called upsilon particle.  Physics. any of a family of heavy, short-lived, neutral mesons that are composed of a bottom quark and its antiquark. Υ, υ

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upsilon British  

/ ˈʌpsɪˌlɒn, juːpˈsaɪlən /

noun

1. the 20th letter in the Greek alphabet (Υ, υ), a vowel, transliterated as y or u

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Etymology

Origin of upsilon

First recorded in 1615–25; from Late Greek ŷ psīlón, literally, “simple u ” (to distinguish it from the digraph oi, pronounced the same in Late Greek )

Example Sentences

And Last: The Empress comes down with a breakthrough case of the upsilon variant and loses her senses of taste and humor.

From Washington Post

They named the signal upsilon, after the shape of the decay-particle trajectories, which resembled the Greek letter.

From Nature

Iota would need no remark but for the custom of placing over it an upsilon, when they commence a syllable, either a very short straight line, or one or two dots.

From Project Gutenberg

These markings supposedly are characteristic of Trimorphodon upsilon.

From Project Gutenberg

Changed what appeared to be upsilon with inverted breve to upsilon with perispomeni in the Greek on page 2.

From Project Gutenberg