Christendom (n.)youdaoicibaDictYouDict[Christendom 词源字典]
Old English cristendom "Christianity, state of being a Christian," from cristen (see Christian) + -dom, suffix of condition or quality. The native formation, crowded out by Latinate Christianity except for sense "lands where Christianity is the dominant religion" (late 14c.). Similar formations in Scandinavian languages.[Christendom etymology, Christendom origin, 英语词源]