Short answers, pulled from the story.
Judeo-Christian is a term used to group Christianity and Judaism together, either in reference to their shared history before Christianity split from Judaism, Christianity's recognition of Jewish scripture as the Old Testament, or values believed to be shared between them. The term originally referred to Jewish converts to Christianity when it first appeared in the 19th century.
The term "Judæo Christian" first appeared in a letter by Alexander McCaul dated the 17th of October, 1821, where it referred to Jewish converts to Christianity. Joseph Wolff used it again in 1829 in reference to a type of church that would observe Jewish traditions to convert Jews.
Historian K. Healan Gaston traced the term's rise in the United States to the 1930s, when the country sought a unified cultural identity to distinguish itself from European fascism and communism. It became part of American civil religion by the 1940s and grew to greater prominence during the Cold War as a way to express opposition to communist atheism.
Many Jewish thinkers criticize the term for perpetuating supersessionism, the theological view that Christianity fulfills and replaces Judaism. Arthur A. Cohen, in The Myth of the Judeo-Christian Tradition, argued the concept was an invention of American politics. Jacob Neusner wrote that "the two faiths stand for different people talking about different things to different people."
Friedrich Nietzsche used the German term "Judenchristlich" to highlight what he saw as neglected continuities between Jewish and Christian worldviews. The expression appears in The Antichrist, published in 1895 but written several years earlier, and a fuller development of his argument can be found in On the Genealogy of Morality.
World War II produced visible symbols of interfaith solidarity, including the much-publicized sinking of a ship whose multi-faith chaplains gave up their lifebelts and stood arm in arm in prayer as it went down. A 1948 postage stamp commemorated their heroism with the words "interfaith in action." The aftermath of the Holocaust was also described as producing a revolution in Christian theology in America regarding attitudes toward Jewish people.