upsilon

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


British Dictionary definitions for upsilon

upsilon

noun
  1. 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.

Online Etymology Dictionary, © 2010 Douglas Harper

upsilon in Medicine

upsilon

n.
  1. The 20th letter of the Greek alphabet.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.