The Collaborative International Dictionary of English v.0.48:

Disciple \Dis*ci"ple\, n. [OE. disciple, deciple, OF. disciple,
   fr. L. discipulus, fr. discere to learn (akin to docere to
   teach; see Docile) + prob. a root meaning to turn or drive,
   as in L. pellere to drive (see Pulse).]
   One who receives instruction from another; a scholar; a
   learner; especially, a follower who has learned to believe in
   the truth of the doctrine of his teacher; an adherent in
   doctrine; as, the disciples of Plato; the disciples of our
   Savior.
   [1913 Webster]

   The disciples, or The twelve disciples, the twelve
      selected companions of Jesus; -- also called the
      apostles.

   Disciples of Christ. See Christian, n., 3, and
      Campbellite.

   Syn: Learner; scholar; pupil; follower; adherent.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Christian \Chris"tian\, n. [L. christianus, Gr. ?; cf. AS.
   cristen. See Christ.]
   [1913 Webster]
   1. One who believes, or professes or is assumed to believe,
      in Jesus Christ, and the truth as taught by Him;
      especially, one whose inward and outward life is conformed
      to the doctrines of Christ.
      [1913 Webster]

            The disciples were called Christians first in
            Antioch.                              --Acts xi. 26.
      [1913 Webster]

   2. One born in a Christian country or of Christian parents,
      and who has not definitely becomes an adherent of an
      opposing system.
      [1913 Webster]

   3. (Eccl.)
      (a) One of a Christian denomination which rejects human
          creeds as bases of fellowship, and sectarian names.
          They are congregational in church government, and
          baptize by immersion. They are also called Disciples
          of Christ, and Campbellites.
      (b) One of a sect (called Christian Connection) of
          open-communion immersionists. The Bible is their only
          authoritative rule of faith and practice.
          [1913 Webster]

   Note: In this sense, often pronounced, but not by the members
         of the sects, kr[imac]s"chan.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Disciples of Christ
    n 1: a Protestant church that accepts the Bible as the only
         source of true Christian faith and practices baptism by
         immersion [syn: Christian Church, Disciples of Christ]