Astronomical event in which
planets line up in a straight line (as described by
Webster 1913 below). Also a common
spelling bee word, even though it's spelled pretty much
just like it sounds.
There's a 5 planet syzygy happening tonight (May 5, 2000) -- the first one since 1966. Some people fear that the combined gravitational pull of so many aligned planets will tear the Earth asunder. Hasn't happened yet.