The Massachusetts court system resembles a pyramid. Cases commence in one of the seven trial court departments (Superior Court, District Court, Boston Municipal Court, Housing Court, Juvenile Court, Land Court, and Probate and Family Court), and are first decided there. Cases are initiated in the particular court which has subject matter and geographic jurisdiction over the issues and parties involved.

Cases are generally described as criminal or civil in nature. Criminal cases are initiated by the government and involve an accusation that a named individual ("defendant") has violated one of many state statutes that enforce public codes of behavior. The government is represented by the Attorney General or a District Attorney ("prosecutor"). At a criminal trial the burden is on the government to prove its case beyond a reasonable doubt. This well-known standard was first articulated in 1850 by Massachusetts Chief Justice Lemuel Shaw in Commonwealth v. Webster, 5 Cush. 386, 59 Mass. 295 (1850).  

In contrast, an ordinary individual ("plaintiff") may initiate a civil complaint stating a legal grievance against other people, entities such as corporations, and even the government (all known as "defendant"), if they cannot resolve a dispute or believe that some legal right has been violated. In civil actions, the parties develop their cases through discovery, requesting information and deposing (questioning) potential witnesses.    

In trial courts, decisions are rendered by the fact-finder (which will have been identified as judge or jury) 6 following testimony by witnesses and arguments by attorneys (or by the parties themselves, if they are not represented by counsel). 7 Physical evidence, such as photographs, a weapon, or relevant documents, may also be admitted in evidence.

After reviewing all the evidence and considering the arguments of counsel, the fact-finder (jury or judge) reaches a verdict. That usually concludes the proceedings at the trial court.

Following a verdict or judgment, the appellate process begins. However, there is no appellate process if a defendant who was charged with a crime is acquitted. The Double Jeopardy clause of the Massachusetts Constitution 8 prohibits the government from appealing an acquittal.