In the United Kingdom and other Commonwealth countries, an indictable offence is a crime that may be punished by a prison term of more than six months or a fine over a certain dollar amount. The term for the same type of offence in the United States is a felony.
A trial for an indictable offence must be authorized by an indictment and not just an information. Depending on the legal system involved, the indictment can be issued by a grand jury, by a judge after a preliminary hearing or by an executive officer of the government (usually, the Attorney-General) by preferred indictment. In the former two cases, the prosecutor must show to the satisfaction of the grand jury or the judge that reasonable and probable cause exists to believe the defendant committed the crime.
A defendant facing an indictment may waive a preliminary hearing and elect to proceed with a trial before an inferior court judge unless the offence is very serious, such as murder or kidnapping, where an indictment is mandatory. However, the defendant is entitled to elect to have the trial heard by a superior court judge, or a jury with a superior court judge. Again, for the most serious offences, a jury is mandatory.