COMMISSIONER, officer. One who has a lawful commission to execute a public office. In a more restricted sense it is one who is authorized to execute. a particular duty, as, commissioner of the revenue, canal commissioner. The term when used in this latter sense is not applied, for example, to a judge. There are commissioners, too, who have no regular commissions and derive their author from the elections held by the people. County commissioners, in Pennsylvania, are officers of the latter kind.