Webster's Revised Unabridged Dictionary · 1913

Christianity

Christianity , noun

[Old English cristiente, Old French cristienté, French chrétienté, from Latin christianitas. ]

1.
The religion of Christians; the system of doctrines and precepts taught by Christ.
2.
Practical conformity of one's inward and outward life to the spirit of the Christian religion
3.
The body of Christian believers. [Obsolete]
To Walys fled the christianitee Of olde Britons. — Chaucer