Orthodoxy (from Ancient Greek ὀρθοδοξία (orthodoxía) 'righteous/correct opinion')[1][2] is adherence to a purported "correct" or otherwise mainstream- or classically accepted creed, especially in religion.[3]
Orthodoxy within Christianity refers to acceptance of the doctrines defined by various creeds and ecumenical councils in antiquity, but different Churches accept different creeds and councils. Such differences of opinion have developed for numerous reasons, including language and cultural barriers. In the Christian world, Eastern Orthodoxy and Oriental Orthodoxy are sometimes referred to simply as "the Orthodox" or "Orthodoxy".
In some English-speaking countries, Jews who adhere to all the contemporarily-applicable commandments legislated in the Written and Oral Torah are often called Orthodox Jews. As this can include many Jews that may not necessarily identify with the term "Orthodox", such as many Masorti Jews, Jewish communities that consider themselves Orthodox are normally united through a diverse, but shared Hashkafic origin from the period of 1818-1821.[4][5][6]
Sunni Islam is sometimes referred to as "Orthodox Islam".