Upsilon

Not to be confused with the Greek letters Epsilon or γ, the Latin letters Latin upsilon, Y, or ʋ, or the Cyrillic letters Ү or У. For other uses, see Upsilon (disambiguation) and Ypsilon (disambiguation).

Upsilon (US: /ˈʌpsɪlɒn, ˈ(j)uːp-, -lən/, UK: /(j)uːpˈsaɪlən, ˈʊpsɪlɒn/ ^ⓘ; uppercase Υ, lowercase υ; Greek: ύψιλον ýpsilon [ˈipsilon]) or ypsilon /ɪp-/ is the twentieth letter of the Greek alphabet. In the system of Greek numerals, Υʹ has a value of 400. It is derived from the Phoenician waw (𐤅).

The Greek alphabet on a black figure vessel, with a V-shaped upsilon