Is it “a fifth wheel” or “a third wheel?” In fact, does choosing one idiom over the other make any difference? The truth is they have identical meanings, but there are certain situations when using one of them is more appropriate than the other.
To learn how to use these common idioms, here are the definitions of each, along with some examples and a few words about the origin.
A third wheel—Meaning and example
If someone is a third wheel, it means they are a burden, an unnecessary and often unwelcomed member of a group of people. It’s most commonly used in a situation when there are one or more couples, and this other person that’s referred to as the “odd man out.”
Usually, a person calls themselves a 3rd wheel if they feel like it in a given situation.
I’m the only one without a date here. I feel like a third wheel.
A fifth wheel — Meaning and example
Just like someone who’s a third wheel, a fifth wheel is a superfluous person in a group of people, a tagalong. The fifth wheel idiom is more common than “the third wheel” because you can use it in situations when there’s one person that doesn’t fit in a group of people, no matter if there are only couples or not.
I think Amy is a fifth wheel in the company, so I’ll have to fire her.
Our godfather was the fifth wheel on our honeymoon.
What about the origin?
These idioms are based on the idea that there are only four wheels in a wagon or carriage or only two wheels on a bicycle, so a fifth or third wheel would be unnecessary. They date back to the 17th century.
So, is it “a fifth wheel” or “third wheel?”
The bottom line is both idioms can be used interchangeably as they have the same meaning, describing a person that doesn’t fit a specific group of people.
Even though “a third wheel” is more appropriate for situations with couples, you can still use it when talking about an unnecessary or unwelcome person in any group of people.