|upsilon (ˈʌpsɪˌlɒn, juːpˈsaɪlən)|
|the 20th letter in the Greek alphabet (Υ, υ), a vowel, transliterated as y or u|
|[C17: from Medieval Greek u psilon simple u, name adopted for graphic u to avoid confusion with graphic oi, since pronunciation was the same for both in Late Greek]|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
|a scrap or morsel of food left at a meal.|
upsilon up·si·lon or yp·si·lon (ŭp'sə-lŏn', y&oomacr;p'-)
Symbol υ The 20th letter of the greek alphabet.