Mark vs Gospel According to Mark

Mark and Gospel According to Mark both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mark	Yes	No	No	No
Gospel According to Mark	Yes	No	No	No

As nouns, Mark and Gospel According to Mark are synonyms defined as:

Mark and Gospel According to Mark: the shortest of the four Gospels in the New Testament

Other synonyms of Mark include Gospel of Mark.

Mark (noun)	Gospel According to Mark (noun)
the shortest of the four Gospels in the New Testament	the shortest of the four Gospels in the New Testament
Apostle and companion of Saint Peter; assumed to be the author of the second Gospel