In Special Relativity desynchronization is the unsung hero of the solutions to many, if not all, relativity paradoxes.
Two knights travel toward each other at high speed. Each sees the other knight length contracted, so each expects his lance will hit the other and the other's lance will not hit him. However, once they collide, both lances hit. Each knight sees his lance hit the other knight first, then sees the other knight's lance extend as the speed of light catches up with the atoms in the lance to say "stop". In the end, both knights are knocked off the horses, but there is disagreement as to which knight got knocked off first. An observer in the middle will see both knights knocked off simultaneously.
This word was used in the manual for a Macintosh relativity tutorial program called RelLab but is not common usage.
