I love this word because of all the tails. If you wrote it in an eighteenth century font with a long s and a long z then the word would look like a branch full of monkeys. I think that's rather lovely.
How do you say it? The first bit as in sizzle, the rest to rhyme with midgy.
And what does it mean?
Oh, all sorts of things. It describes the moment when the sun, the earth, and another celestial body lie in a straight line; it's a technical term in classical verse; it can be a pair, usually of opposites (as in chalk and cheese or Laurel and Hardy); and it's what happens to protozoans when they begin to feel a bit frisky.
Altogether syzygy is a lovely word, though I must admit it's not likely to crop up unless you see a full moon (the moon is at syzygy when full) or know a couple who are completely unalike.
Walter Crane 1874.
Come to think about it, though, everyone knows one of those.
Word To Use Today: syzygy. This word comes from the Greek suzugia, which means yoked together, from sun, together, and zugon, which means a yoke.