WordNet (r) 3.0 (2006):

Gospels
    n 1: the four books in the New Testament (Matthew, Mark, Luke,
         and John) that tell the story of Christ's life and
         teachings [syn: Gospel, Gospels, evangel]

Easton's 1897 Bible Dictionary:

Gospels
   The central fact of Christian preaching was the intelligence
   that the Saviour had come into the world (Matt. 4:23; Rom.
   10:15); and the first Christian preachers who called their
   account of the person and mission of Christ by the term
   _evangelion_ (= good message) were called _evangelistai_ (=
   evangelists) (Eph. 4:11; Acts 21:8).

     There are four historical accounts of the person and work of
   Christ: "the first by Matthew, announcing the Redeemer as the
   promised King of the kingdom of God; the second by Mark,
   declaring him 'a prophet, mighty in deed and word'; the third by
   Luke, of whom it might be said that he represents Christ in the
   special character of the Saviour of sinners (Luke 7:36; 15:18);
   the fourth by John, who represents Christ as the Son of God, in
   whom deity and humanity become one. The ancient Church gave to
   Matthew the symbol of the lion, to Mark that of a man, to Luke
   that of the ox, and to John that of the eagle: these were the
   four faces of the cherubim" (Ezek. 1:10).

     Date. The Gospels were all composed during the latter part of
   the first century, and there is distinct historical evidence to
   show that they were used and accepted as authentic before the
   end of the second century.

     Mutual relation. "If the extent of all the coincidences be
   represented by 100, their proportionate distribution will be:
   Matthew, Mark, and Luke, 53; Matthew and Luke, 21; Matthew and
   Mark, 20; Mark and Luke, 6. Looking only at the general result,
   it may be said that of the contents of the synoptic Gospels
   [i.e., the first three Gospels] about two-fifths are common to
   the three, and that the parts peculiar to one or other of them
   are little more than one-third of the whole."

     Origin. Did the evangelists copy from one another? The opinion
   is well founded that the Gospels were published by the apostles
   orally before they were committed to writing, and that each had
   an independent origin. (See MATTHEW, GOSPEL OF.)