A ruling is an official decision made by someone in authority, especially a judge, referee, or other person whose job is to settle disputes or interpret rules. When a judge makes a ruling in a courtroom, the judge decides how the law applies to a particular situation. When a referee makes a ruling on the field, the referee determines whether a play was legal.

Rulings matter because they resolve disagreements and establish what happens next. If two students argue about whether a ball landed in or out during kickball, the gym teacher's ruling settles it. Once the ruling is made, people are expected to accept it and move forward, even if they disagreed at first. In higher courts, a judge's ruling can affect thousands or even millions of people. For example, the Supreme Court's 1954 ruling in Brown v. Board of Education declared that racial segregation in public schools violated the Constitution, changing American education forever.

The word can also describe the group currently in power, like a ruling party in government or a ruling family in a monarchy. These meanings connect to the idea of being in control and making decisions that others must follow.