Acceleration Clause

An acceleration clause, in the law of contracts, is a term that fully matures the performance due from a party upon a breach of the contract. Such clauses are most prevalent in mortgages and similar contracts to purchase real estate in installments.Suppose, for example, the contract was for A to purchase Blackacre from B for $100,000, to be paid in 5 monthly installments of $20,000. If A makes the first two payments, but fails to make the third payment, an acceleration clause would require that A must immediately pay B the entire balance of $60,000, or lose his right to purchase Blackacre (without getting a refund of his $40,000).
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A contract stating that the unpaid balance becomes due and payable if specific actions transpire, such as failure to make interests payments on time.

A clause in a contract that states that if a payment is missed, or some other default occurs (such as the debtor becoming insolvent), then the contract is fully due immediately. - (read more on Acceleration clause)