up·si·lon
| \ ˈüp-sə-ˌlän
, ˈyüp-
, ˈəp-, -lən, British usually yüp-ˈsī-lən \
, ˈyüp-
, 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
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“Upsilon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/upsilon. Accessed 28 Feb. 2021.
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Time Traveler for upsilon
The first known use of upsilon was in 1621
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