A fortunate unforseen circumstance. An unexpected perk as a result of any given chain of events.
An obvious melding of the
words fortunate + unforseen + circumstance.
This word originated as a forcumstantial product of a
slip of the tounge by a
friend attempting to say "Fortunate unforseen circumstance".
Its obvious poetry, and the way it trips lightly off the tounge make it a forcumstantial addition to any cutting edge lexicon or meme cache.