quartet, quartette or quartett /kwör-tetˈ/

1. A set of four
2. A composition for four voices or instruments
3. A set of performers or instruments for such compositions

• ordinates
• ordinating
• ordination
• ordinations
• ordinee
• ordinees
• ordnance
• ordnance datum
• ordnances
• Ordnance Survey
• ordonnance
• ordonnances
• Ordovician
• ords
• ordure
• ordures
• ordurous
• o're
• ore
• oread
• oreades
• oreads
• ore bodies
• ore body
• orecchiette