high commissioner:
(plural: ‘high commissioners‘)

Sir James Bevan, the British High Commissioner to India, interacting with some Indian
a person (high diplomatic official) who represents one commonwealth country in another;
a United Kingdom official diplomatic representative (ambassador) in countries such as India, Canada, Australia, etc.;
a chief officer of an international commission, such as International Trade Commission, International Peace Commission, International Human Rights Commission, etc.,

Ms Sadako Ogata, former UN High Commissioner for Refugees, visiting a refugee camp in Africa
A high commissioner is the position or title given to the head or chief of an office or official body of people called a ‘commission’ to manage certain specific or general issues between two countries or among several countries at the United Nations Organisation.
The high commissioner of a high commission office in a Commonwealth country is equivalent to an ambassador of an embassy in a non-Commonwealth country.
The Australian High Commissioner expressed his wish that the game of international cricket be started again in Pakistan.
The United Nations Organisation (U N O) has several ‘commissions’ — human rights commission, refugees commission, economic commission for various countries/continents — and each commission has a High Commissioner whose responsibility it is to find out the problems, suggest ways to rectify the problems and oversee the implementation of the methods.
