In US law, one party can bring a lawsuit against another party in court.   In civil cases, the party bringing the suit — called the plaintiff — generally claims to have incurred loss through actions of the other party – the defendant.   In criminal cases, the state — whose legal representative is called ‘the prosecution’ — charges the defendant with breaking the law.   The court decides the case; judgement may include remedy of the loss and damages in civil cases, or sentencing in criminal cases, plus injunctions to force action and other legal consequences.    The overall conduct of a lawsuit is called ‘litigation.’  The parties on both sides are generically ‘litigants’, and the attorneys who represent them are ‘litigators.’
 
