[yoop-suh-lon, -luh n, uhp-; especially British yoop-sahy-luh n]
- 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
- the 20th letter in the Greek alphabet (Υ, υ), a vowel, transliterated as y or u
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
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.
Online Etymology Dictionary, © 2010 Douglas Harper
- The 20th letter of the Greek alphabet.