What is a third wheel?

A third wheel is a term used to describe a person who hangs out with a couple as a friend or companion but is not romantically involved with either of them. This can sometimes make the third wheel feel left out or awkward, as they may feel like they are intruding on the couple's time together. However, being a third wheel can also be a fun and enjoyable experience, as it allows for different dynamics in a social setting and can lead to new friendships and experiences. It is important for the couple to make the third wheel feel included and valued in order to avoid any feelings of alienation.