An arraignment hearing is a court proceeding where the charges against you are read and you are to submit a plea. The arraignment is often called an “initial appearance” because it is typically the first time you appear in court.
Grand jury proceedings are similar to preliminary hearings as they are both for determining whether there is enough evidence to bring criminal charges or an indictment against you. The prosecutor will work with a grand jury to make a decision. In the federal system, a grand jury can be 16 to 23 people.
If the case goes to a grand jury indictment, no preliminary hearing is needed. A preliminary hearing is a “trial before the trial” where the judge decides whether there is enough evidence to force you to stand trial. It involves lawyers on both sides and the judge.