upsilon

[yoop-suh-lon, -luh n, uhp-; especially British yoop-sahy-luh n]

noun

the 20th letter of the Greek alphabet (Υ, υ).
the vowel sound represented by this letter.
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. Symbol: Υ, υ

Origin of upsilon

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

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for upsilon

Historical Examples of upsilon

This species is the ypsilon of Borkhausen, and the upsilon of other authors.
The Moths of the British Isles, Second Series
Richard South
She issued an order, therefore, that for a certain time Upsilon was to have no playthings.
Walter Pieterse
Multatuli

British Dictionary definitions for upsilon

upsilon

noun

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

Word Origin for upsilon

C17: from Medieval Greek u psilon simple u, name adopted for graphic u to avoid confusion with graphic oi, since pronunciation was the same for both in Late Greek

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

Word Origin and History for upsilon

"20th letter of the Greek alphabet," 1640s, from Greek u psilon, literally "a mere (or bare) 'u;' " so called in contradistinction to the diphthongs -oi-, -ei-, which are pronounced exactly like upsilon.

upsilon in Medicine

upsilon

The 20th letter of the Greek alphabet.