What is a Chief Justice?

The chief justice is the presiding member of a supreme court in any of many countries with a justice system based on English common law, such as the High Court of Australia, the Supreme Court of Canada

Explanation:

The chief justice is appointed by the president with the advice and consent of the Senate and has life tenure. His primary functions are to preside over the Supreme Court in its public sessions when the court is hearing arguments and during its private conferences when it is discussing and deciding cases.

Chief justice, the presiding judge in the Supreme Court of the United States, and the highest judicial officer of the nation.