To overrule means to use your authority to reject or reverse someone else's decision. When a judge overrules an objection in court, she's saying, “No, that objection doesn't stand,” and allowing the lawyer to continue. When parents overrule a babysitter's decision to let kids stay up late, they're using their greater authority to change that choice.

A principal might overrule a teacher's punishment if it seems too harsh. The Supreme Court can overrule lower court decisions. The school board might overrule the principal's decision to cancel a field trip.

Being overruled doesn't necessarily mean you made a bad decision. Sometimes people with different perspectives or more information use their authority to make a different call. If a referee overrules a line judge in tennis, it means the referee saw the play differently and has the final say.

Notice that you need actual authority to overrule someone. You can't overrule your sibling's bedtime just because you disagree with it. The power to overrule comes from holding a higher position in whatever system you're working within.