In common law legal systems, an indictment is a formal accusation that a person has committed a criminal offense.
In those jurisdictions which retain the concept of a felony, the serious criminal offence would be a felony; those jurisdictions which have abolished the concept of a felony often substitute the concept of an indictable offence, i.e. an offence which requires an indictment.
Traditionally an indictment was handed up by a grand jury, which returned a "true bill" if it found cause to make the charge, or "no bill" if it did not find cause. Most common law jurisdictions (except for much of the United States) have abolished grand juries.