(n.) The 20th letter (/, /) of the Greek alphabet, a vowel having originally the sound of / as in room, becoming before the 4th century b. c. that French u or Ger. u. Its equivalent in English is u or y.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). upsilon. Retrieved September 20, 2026, from http://smartdefine.org/upsilon/definitions/2078143 |
| Chicago | Webster's. 2011. "upsilon" http://smartdefine.org/upsilon/definitions/2078143 (accessed September 20, 2026). |
| Harvard | Webster's 2011, upsilon, Smart Define, viewed 20 September, 2026, <http://smartdefine.org/upsilon/definitions/2078143>. |
| MLA | Webster's. "upsilon" 28 May 2011. Web. 20 September 2026. <http://smartdefine.org/upsilon/definitions/2078143> |