Precedent

A court decision in an earlier case with facts and legal issues similar to a dispute currently before a court. Judges will generally "follow precedent" — meaning that they use the principles established in earlier cases to decide new cases that have similar facts and raise similar legal issues. A judge will disregard precedent if a party can show that the earlier case was wrongly decided, or that it differed in some significant way from the current case.

Source: U.S. Courts