upsilon

noun
up·​si·​lon | \ ˈüp-sə-ˌlän How to pronounce upsilon (audio) , ˈyüp- How to pronounce upsilon (audio) , ˈəp-, -lən, British usually yüp-ˈsī-lən \

Definition of upsilon

1 : the 20th letter of the Greek alphabet — see Alphabet Table
2 : any of a group of unstable electrically neutral elementary particles of the meson family that have a mass about 10 times that of a proton

First Known Use of upsilon

1621, in the meaning defined at sense 1

History and Etymology for upsilon

Middle Greek y psilon, literally, simple y; from the desire to distinguish it from oi, which was pronounced the same in later Greek

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The first known use of upsilon was in 1621

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Last Updated

27 Jan 2020

Cite this Entry

“Upsilon.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/upsilon. Accessed 29 January 2020.

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to assert without proof or before proving

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