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

• ancestrally
• ancestress
• ancestresses
• ancestries
• ancestry
• ancho
• anchor
• anchorage
• anchorages
• Anchor Boys
• anchor buoy
• anchor buoys
• anchored
• anchor escapement
• anchoress
• anchoresses
• anchoret
• anchoretic
• anchoretical
• anchorets
• anchor-hold
• anchor-ice
• anchoring
• anchorite
• anchorites