I agree. It's hardly a word in common use. According to Dictionary.com there's a specialised use in meteorology, "Of or relating to data obtained nearly simultaneously over a large area of the atmosphere." However, I suspect that the more general meaning of "summary" or "overall view" was intended.
BTW, I assume the spelling in the thread title is a typo?
Build a man a fire and he's warm for a day. Set a man on fire and he's warm for the rest of his life.
Actually I learnt 'synoptic' from weather charts, and for a long time that was the only thing I knew it for. (I supposed a synoptic chart was one that shows rain, pressure, temperature and so on all on the same overview, over a wide area.) Later I came across it in (translation of) Wittgenstein, and was pulled up at it. I had to deconstruct it as just the adjective of synopsis = overview, summary.
The first three Gospels of the New Testament (Matthew, Mark and Luke) are called the synoptic gospels because German scholars took the original Greek texts, lined up the corresponding sayings, parables and histories from these three books and noticed that there were some striking correspondences, sometimes nearly entire paragraphs of identical text. From the pattern of these correspondences they deduced that Matthew and Luke copied from Mark, so Mark was actually the earliest of the three; Matthew and Luke were almost certainly unaware of each other; Matthew and Luke also copied sayings of Jesus (but no historical narrative) from from a lost source, dubbed Q (from the German quelle, or source); John was independent of all three and Q.
