A person who whom one has an extra-marital affair with.
Psycho bitch's mother wasn't shocked when she found out psycho bitch was her dad's bit on the side.
by Kung-fu Jesus July 27, 2004
1 more definition
Noun- When a person is not exactly what you would call "normal"
yesterday, I was in the store and I saw a woman sittin' there just rocking back and foward, justa hummin'.... she was a bit on the side.
by GA girl February 24, 2006