Accident

n. casualty, misadventure; mishap; failure, incident

For alternate meanings, see: Accident (fallacy), Accident (philosophy), Accident (film), Accident, Maryland, and Car accidents. An accident is a specific, identifiable, unexpected, unusual and unintented external event which occurs in a particular time and place, without apparent cause but with marked effect. It implies a generally negative probabilistic outcome which may have been avoided or prevented had circumstances leading up to the accident been recognized, and acted upon, prior to its occurrence.
See more at Wikipedia.org...

Accident, n 1. an unusual, unforeseen event. n 2. an unusual or unexpected result attending the performance of a usual or necessary act or event. [more]Accident - Community and Resources

Noun
1. a mishap; especially one causing injury or death
(hypernym) mishap, misadventure, mischance
(hyponym) collision
2. anything that happens by chance without an apparent cause
(synonym) fortuity, chance event
(hypernym) happening, occurrence, natural event
(hyponym) hap

n. accident, casualty; trouble, wreck; accidence