vicissitude \vih-SIS-ih-tood; -tyood\, noun:
1. Regular change or succession from one thing to another; alternation; mutual succession; interchange.
2. Irregular change; revolution; mutation.
3. A change in condition or fortune; an instance of mutability in life or nature (especially successive alternation from one condition to another).
This man had, after many vicissitudes of fortune, sunk at last into abject and hopeless poverty.
-- Thomas Macaulay