Fifth wheel (disambiguation)
WordNet
noun
(1) A steering bearing that enables the front axle of a horse-drawn wagon to rotate
(2) An extra car wheel and tire for a four-wheel vehicle
(3) Someone or something that is unwanted and unneeded
WiktionaryText
Noun
- A type of trailer hitch, which consists of a horseshoe-shaped plate on a multi-directional pivot, with a locking pin to couple with the kingpin of a truck trailer.
- A very large truck trailer; an 18-wheeler.
- A very large trailer that is towed with a pickup truck.
- Anything superfluous or unnecessary.
- As the third person along on their date, I felt like a fifth wheel.
- I felt like a fifth wheel when they started giggling and making out during dinner.