This refers to the process of a person admitting to guilt in a criminal or civil case, often in the hopes of receiving a lesser punishmen

This is called a "plea deal," or "plea bargain."

Explanation: Basically the defendant is pleading guilty to a less harsh crime than what they were initially charged with to avoid a trial, thus it being called a "plea deal" or "plea bargain." The defendant exchanges his guilty plea for serving lesser time in jail or prison.