accident

1. 1. An unexpected and undesirable event, especially one resulting in damage or harm: car accidents on icy roads.
   2. An unforeseen incident: A series of happy accidents led to his promotion.
   3. An instance of involuntary urination or defecation in one's clothing.
2. Lack of intention; chance: ran into an old friend by accident.
3. Logic. A circumstance or attribute that is not essential to the nature of something.

[Middle English, chance event, from Old French, from Latin accidēns, accident-, present participle of accidere, to happen : ad-, ad- + cadere, to fall.]