Security in the form of a bail bond or cash as a guaranty that a released prisoner will present himself for trial. The security may be lost if the released person does not appear in the court as required. Bail bonds are usually required in criminal tax cases.
A bail bondsman, bail bondsperson, bail bond agent or bond dealer is any person, agency or corporation that will act as a surety and pledge money or property as bail for the appearance of a defendant in court. Wikipedia
A bail bond is a written promise signed by a defendant and surety to ensure that a criminal defendant will appear in court at the scheduled time and date, as ordered by the court. The bail amount is set by the court. Investopedia