a government administrator
"The new commissioner announced stricter regulations for the city's waste management system yesterday."
a member of a commission
"The new commissioner arrived at the hearing to review the city's zoning laws."
A member of a commission.
"The new commissioner took her seat at the head of the city planning table to discuss zoning laws."
In plain English: A commissioner is an official who has been given the power to make rules or run a specific group of people.
"The commissioner announced that the new park would open next summer."
Usage: Use commissioner to refer to an official appointed to lead or oversee a specific government board, agency, or department. This title often denotes high-ranking public servants responsible for enforcing laws or managing municipal services.
The word entered English via the path of Middle English and Anglo-Norman before arriving from Medieval Latin. It originally referred to an official appointed to carry out a specific task or duty, closely related to the concept of a commission.