upsilon /ūp-sīˈlon, ŭp-, ūpˈsi- or upˈsi-/ or ypsilon /ip-sīˈlon or ipˈsi-/

1. The twentieth letter of the Greek alphabet (Υ, υ)
2. As a numeral υˈ = 400, ˌυ = 400000
3. A short-lived heavy subatomic particle produced when beryllium nuclei are bombarded with high-energy protons

• ruination
• ruinations
• ruined
• ruiner
• ruiners
• ruing
• ruings
• ruining
• ruinings
• ruin marble
• ruinous
• ruinously
• ruinousness
• ruinousnesses
• ruins
• rukh
• rulable
• rule
• Rule 43
• ruled
• ruleless
• rule of faith
• rule of the road
• rule of three
• rule of thumb