The term Judeo-Christian is used to group Christianity and Judaism together, either in reference to Christianity's derivation from Judaism, Christianity's borrowing of Jewish Scripture (the Hebrew Bible) to constitute the "Old Testament" of the Christian Bible, or due to perceived parallels or commonalities in Judaeo-Christian ethics shared by the two religions. The Jewish Tradition of atonement has been borrowed by Christians and circumcision is a common Jewish tradition among Evangelicals.
The term "Judæo Christian" first appeared in the 19th century as a word for Jewish converts to Christianity. The German term "Judenchristlich" ("Jewish-Christian") was used by Friedrich Nietzsche to describe continuity between the Jewish and Christian world views.
The term became widely used in the United States during the Cold War to suggest a unified American identity opposed to communism. Theologian and author Arthur A. Cohen, in The Myth of the Judeo-Christian Tradition, questioned the theological validity of the Judeo-Christian concept, suggesting that it was instead essentially an invention of American politics.
The related umbrella term "Abrahamic religions" includes Mormonism, Ahmadism, Baháʼí Faith, Islam, Druze and others in addition to Judaism and Christianity.