'Constantinian symbol' definitions:

Definition of 'Constantinian symbol'

From: GCIDE
  • XP \XP\ [Belongs here in appearance only.] The first two letters of the Greek word XRISTOS, Christ; -- an abbreviation used with the letters separate or, oftener, in a monogram, often inclosed in a circle, as a symbol or emblem of Christ. It use as an emblem was introduced by Constantine the Great, whence it is known as the
  • Constantinian symbol, or
  • monogram. See Labarum. [Webster 1913 Suppl.]