To listen in on somebodies conversation without being invited. I.E.-You're on the bus talking with a friend and somebody you don't even know either tries to get into the conversation or is obviously listening.
Definitions include: A slang way of saying, to start all over or back to yhe basics. Compare to: Beginning, The Start or The Bottom. She kept hanging with thots and ended up losing her relationship, job, car and apt. Now she's back at Square 1.