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

• phototropy
• phototube
• phototubes
• phototype
• phototyped
• phototypes
• phototypesetter
• phototypesetters
• phototypesetting
• phototypic
• phototypies
• phototyping
• phototypy
• photovoltaic
• photovoltaic cell
• photovoltaics
• photoxylography
• photozincograph
• photozincographs
• photozincography
• phots
• phr
• phrasal
• phrasal verb
• phrasal verbs