His Honour or Her Honour is an honorific prefix which is traditionally applied to certain classes of people, in particular justices and judge

Judge

A judge is a person who presides over court proceedings, either alone or as part of a panel of judges. The powers, functions, method of appointment, discipline, and training of judges vary widely across different jurisdictions. The judge is supposed to conduct the trial impartially and in an open...

s and mayor

Mayor

In many countries, a Mayor is the highest ranking officer in the municipal government of a town or a large urban city....

s. In Australia and the United States, the prefix is also used for magistrate

Magistrate

A magistrate is an officer of the state; in modern usage the term usually refers to a judge or prosecutor. This was not always the case; in ancient Rome, a magistratus was one of the highest government officers and possessed both judicial and executive powers. Today, in common law systems, a...

s (spelled in the American style, "Honor").

In the Northern Territory the Administrator is referred to as His Honour.

In England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 and Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

, it is used as a prefix for circuit judges. In Northern Ireland

Northern Ireland

Northern Ireland is one of the four countries of the United Kingdom. Situated in the north-east of the island of Ireland, it shares a border with the Republic of Ireland to the south and west...

 the prefix is also used for county court

County Court

A county court is a court based in or with a jurisdiction covering one or more counties, which are administrative divisions within a country, not to be confused with the medieval system of county courts held by the High Sheriff of each county.-England and Wales:County Court matters can be lodged...

 judges.

In Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, His Honour or Her Honour is used as a title for the Lieutenant Governor

Lieutenant Governor (Canada)

In Canada, a lieutenant governor is the viceregal representative in a provincial jurisdiction of the Canadian monarch and head of state, Queen Elizabeth II, who resides predominantly in her oldest realm, the United Kingdom...

 of a province

Provinces and territories of Canada

The provinces and territories of Canada combine to make up the world's second-largest country by area. There are ten provinces and three territories...

 while in office. The spouse of a Lieutenant Governor is also addressed as His or Her Honour only while the Lieutenant Governor is in office. The Honourable

The Honourable

The prefix The Honourable or The Honorable is a style used before the names of certain classes of persons. It is considered an honorific styling.-International diplomacy:...

is a courtesy title retained for life for a former Lieutenant Governor.