A more thorough explanation:

A writ of certiorari is a legal order that a higher court issues to a lower court, requesting the lower court to send up the records of a case for review. The term "certiorari" comes from Latin and means "to be informed." This writ is used to determine whether a lower court has made an error of law that requires correction by a higher court.

The writ of certiorari is commonly used by the United States Supreme Court to select cases it hears. The Supreme Court receives thousands of petitions each year, but it only grants certiorari to a small percentage of them. The court uses the writ to review cases that involve important legal questions or conflicts between lower courts.

For example, if a state court of appeals makes a decision that conflicts with a decision made by another state court of appeals, the Supreme Court may issue a writ of certiorari to resolve the conflict and establish a uniform rule of law.

Another example is when a federal court of appeals makes a decision that conflicts with a decision made by a state supreme court. In this case, the Supreme Court may issue a writ of certiorari to determine which court's decision should prevail.

In summary, a writ of certiorari is a legal order that allows a higher court to review the decision of a lower court. The writ is used to correct errors of law, resolve conflicts between lower courts, and establish uniform rules of law.