The Term Patriarch, in the Old Testament, refers to Abraham, Isaac, and Jacob, since they were the fathers of the Jewish people.
When we are speaking about Christian times, patriarch refers to a prelate who holds precedence over primates, metropolitans, and bishops. In order of dignity. There are the patriarchs of Rome who is The Pope, Constantinople (modern-day Istanbul), Alexandria, Antioch, and Jerusalem.
Catholic Eastern Churches, with particular Jurisdiction also known as “SUI JURIS” are shepherded by their correspondent Patriarchs, or Metropolitan.
There are patriarchs of the Armenian, Maronite, Melkite, and Chaldean rites (all Catholics), and there are "minor" patriarchs in Venice, Lisbon, and in the West and East Indies.