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

• erodes
• erodible
• eroding
• erodium
• erodiums
• erogenic
• erogenous
• erogenous zone
• erogenous zones
• EROM
• Eros
• erose
• erosion
• erosional
• erosions
• erosive
• erostrate
• erotema
• erotemas
• eroteme
• erotemes
• eroteses
• erotesis
• erotetic
• erotic