(1):

(n.) The name received at baptism; or, more generally, any name or appelation.

(2):

(n.) The profession of faith in Christ by baptism; hence, the Christian religion, or the adoption of it.

(3):

(n.) The whole body of Christians.

(4):

(n.) That portion of the world in which Christianity prevails, or which is governed under Christian institutions, in distinction from heathen or Mohammedan lands.