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

• gadoid
• gadoids
• gadolinite
• gadolinites
• gadolinium
• gadoliniums
• gadroon
• gadrooned
• gadrooning
• gadroonings
• gadroons
• gads
• gadsman
• gadsmen
• gadso
• Gadus
• gadwall
• gadwalls
• gadzooks
• gae
• Gaea
• Gaea hypothesis
• Gaekwar
• Gael
• Gael.