Fifth-wheel meaning
An additional wheel carried on a four-wheeled vehicle as a spare.
noun
An extra and unnecessary person or thing.
noun
A wheel or portion of a wheel placed horizontally over the forward axle of a carriage to provide support and stability during turns.
noun
A similar device over the rear axle or axles of a tractor or pickup truck, serving as a coupling for a semitrailer.
noun
An unnecessary or superfluous person or thing.
noun
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A horizontal wheel-like structure placed over the front axle of a carriage or wagon to support it on turns.
noun
A similar structure on the rear of the cab of a tractor-trailer, serving as a coupling for attaching the trailer.
noun
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(idiomatic) 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.
noun