Meaning
A person or thing that is unnecessary, surplus to requirements, or in the way, especially an extra person who feels awkward or out of place in a group, such as a single person accompanying two couples. In modern everyday use 'third wheel' has largely displaced it in this personal sense. Informal; describes an uncomfortable, self-deprecating social position rather than an insult directed at worthlessness. Regional use: General English; 'fifth wheel' itself now more North American, with 'third wheel' dominant in the UK.
Origin
The image is of a wheel added to a wagon or carriage that needs only four, making the fifth redundant and useless. Dictionary.com traces a possible early figurative use to Thomas Dekker's play 'Match Me in London' (1631), while the figurative sense of an unnecessary person or thing was widespread in America by the mid-1800s; the Oxford English Dictionary's earliest record of the mechanical noun 'fifth-wheel' dates from Edward H. Knight's 1874 mechanical dictionary. Ironically, the term later attached itself to a real and essential device, the coupling mechanism on tractor-trailers and RV hitches, descended from a turning plate on horse-drawn carriages, so the literal wheel is no longer useless even though the idiom still is.
Research Sources
References used to check this entry’s meaning, history, or documented forms.
Variants
- fifth wheel on the cart
- fifth wheel on the wagon
- superfluous fifth wheel
- third wheel
Usage Examples
- When his two friends started dating, he felt like a fifth wheel on their outings.
- The committee already had a treasurer, so the new appointee was a fifth wheel with nothing to do.
- Rather than be a fifth wheel at the dinner party, she volunteered to help in the kitchen.