Excessive bail refers to the practice of setting a bail amount that is unreasonably high and disproportionate to the nature of the crime charged. This concept is rooted in the Eighth Amendment of the U.S. Constitution, which prohibits excessive bail, ensuring that individuals are not unjustly penalized before their trial. The purpose of bail is to ensure a defendant's appearance in court, and when bail is set excessively high, it can lead to unfair incarceration, particularly for those who may be innocent or have limited financial means.