Why are Matthew, Mark, and Luke called the synoptic gospels? The first three gospels are sometimes known as the "synoptic" gospels. What does this term mean, and how does it differentiate them from the gospel of John?
Syn- means same (as in synchronize, same time), and optic of course refers to sight.  The three first Gospels are syn-optic because they see alike; they basically tell the same story as each other, covering many of the same events.  John, on the other hand, focuses on a lot of different material than the other authors, and has a very high percentage of unique content.