Word Study
upsilon
CIDE DICTIONARY
upsilon, n. [Gr. 'y^ psilo`n bare, mere, simple y.].
The 20th letter (room, becoming before the 4th century b. c. that French u or Ger. Ü. Its equivalent in English is u or y . [Webster 1913 Suppl.]
OXFORD DICTIONARY
upsilon, n. the twelfth letter of the Greek alphabet.
Etymology
Gk, = slender U f. psilos slender, with ref. to its later coincidence in sound with Gk oi
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