A word very valuable in situations where you are playing Scrabble and wish to temporarily infuriate your opponent with your apprent complete disregard for the simple dictionary-based rules of the game, only to have them remark in your favour with a certain astonishment when they discover it really is a word.
"syzygy?! That's not a word!!"
"It is so! Go ahead look it up!"
"Alright..." (time passes as opponent flicks through the dictionary) "... God damnit..."
The near perfect linear alignment of 3 or more celestial bodies (as in the sun the moon and the earth during a solar eclipse) in a gravatational system.
A total-harmony state achieved by a group of meditation-minded "in tune with the power of the Universe" hippies while engaged in perfectly-in-sync cutting/trimming of paper/fabric with "syzzors".
Performing syzzygy with your weed-puffing buddies can indeed be relaxing, but your hands get tired fairly soon from all of that synchronized snippin'.