Indictment and Complaint
A “criminal complaint” is any piece of paper that – among other things — names the plaintiff (for example, the State of Oregon), the defendant and each of the charges that has been filed against the defendant.
An “indictment” is a specific type of complaint, in which charges – including at least one felony charge – have been approved by the Grand Jury.
The Grand Jury usually only hears one side of the case, and they vote on whether the evidence they hear – if unchallenged – would be enough to support a conviction. Getting an indictment past the Grand Jury is about as difficult for a prosecutor as a professional football team would have in scoring a touchdown, when there is no other team on the field.
An “arraignment” is simply the moment that the defendant appears in court, to be formally presented with the complaint.