ˈkris ə ndəm noun
( -s )
Etymology: Middle English cristendom, from Old English cristendōm, from cristen Christian + -dōm -dom
1.
a. often capitalized , obsolete : christianity 3
b. usually capitalized : christianity 1,2
across the first thousand years of Christendom the principal church was the Roman Catholic Church — F.S.Mead
2. usually capitalized : the portion of the world in which Christianity prevails or which is governed principally under Christian institutions