The difference between Accident and Contingency

Accident as a noun:

An unexpected event with negative consequences occurring without the intention of the one suffering the consequences.

Accident as a noun (transport, vehicle):

Especially, a collision or similar unintended event that causes damage or death.

Accident as a noun:

Any chance event.

Accident as a noun (uncountable):

Chance.

Accident as a noun:

Any property, fact, or relation that is the result of chance or is nonessential.

Accident as a noun (euphemistic):

An instance of incontinence.

Accident as a noun (euphemistic):

An unintended pregnancy.

Accident as a noun (philosophy, logic):

A quality or attribute in distinction from the substance, as sweetness, softness.

Accident as a noun (grammar):

A property attached to a word, but not essential to it, such as gender, number, or case.

Accident as a noun (geology):

An irregular surface feature with no apparent cause.

Accident as a noun (heraldry):

A point or mark which may be retained or omitted in a coat of arms.

Accident as a noun (legal):

casus; such unforeseen, extraordinary, extraneous interference as is out of the range of ordinary calculation.

Accident as a noun (uncountable, philosophy, uncommon):

Appearance, manifestation.

Contingency as a noun (uncountable):

The quality of being contingent, of happening by chance; unpredictability.

Contingency as a noun (countable):

A possibility; something which may or may not happen. A chance occurrence, especially in finance, unexpected expenses.

Contingency as a noun (countable):

An amount of money which a party to a contract has to pay to the other party (usually the supplier of a major project to the client) if he or she does not fulfill the contract according to the specification.

Contingency as a noun (logic, countable):

A statement which is neither a tautology nor a contradiction.