luminosity：光明，光辉；发光度；发光体

词根词缀： -lumin-光,照 + -osity名词词尾

• frenulum
• frenzy
• frequency
• frequent
• fresco
• fresh
• freshman
• freshwater
• fret
• fretful
• fretsaw
• fretted
• fretwork
• friable
• friar
• friary
• fricassee
• friction
• Friday
• fridge
• friend
• friendship
• Friesian
• frieze
• frigate