1. Someone or something that is unwanted and unneeded
   - deadwood 
2. An extra car wheel and tire for a four-wheel vehicle
   - spare 
3. A steering bearing that enables the front axle of a horse-drawn wagon to rotate

Derived forms: fifth wheels

Type of: bearing, car wheel, redundance, redundancy, superfluousness

Encyclopedia: Fifth wheel

• primary sexual characteristic
• primary solid solution
• primary subtractive color for light
• primary subtractive colour for light
• primary syphilis
• primary tooth
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• primate
• Primates
• primateship
• primatology
• Primaxin
• prime
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• primer coat