In hierarchical Western Christianity, an ordinary (from the Latin ordinarius) is an ecclesiastical officer with both pastoral and governmental jurisdiction over a well-defined group of persons granted by Canon law. In the Eastern church, such an officer is called a hierarch, which comes from the Greek word 'ιεραρχης' meaning "high priest."
The term ordinary emphasizes that the power of the officer is not delegated from a higher governmental body but is granted directly from the law, whether that law be the codified 'canon' laws of the church or 'divine' laws which the church sees coming directly from God. Other ecclesiastical officers may exercise governmental or pastoral jurisdiction delegated from one of these officers, but since they are not mentioned in the law, they are not ordinaries.
The power to govern (termed external jurisdiction) is different from pastoral power (also called internal jurisdiction). Governing jurisdiction means Executive, legislative, and/or judicial power, whereas pastoral jurisdiction means the power to teach or supervise. Thus, while a Pastor has pastoral power over the members of his Parish granted by virtue of the law, he is not an ordinary because he does not have governing power. A Vicar general is an ordinary, though, because he possesses both jurisdictions over a Diocese.
The Pope is the local ordinary of Rome. He is also the ordinary, but not the local ordinary, of the Latin Rite church. Roman Catholics also believe that he is also the ordinary of the universal Church.