That arguement you will have to take up with Noah Webster who knew literally every chapter and verse in the Bible. :>}
Gos"pel (?), n. [OE. gospel, godspel, AS. godspell; god God + spell story, tale. See God, and Spell, v.]
1. Glad tidings; especially, the good news concerning Christ, the Kingdom of God, and salvation.
And Jesus went about all Galilee, teaching in their synagogues, and preaching the gospel of the kingdom. Matt. iv. 23.