A more thorough explanation:

Definition: Mahr is a term used in Islamic law that refers to a gift of money or property that a man must give to the woman he marries. The amount and time of payment are agreed upon by both parties before the marriage takes place. If the payment time is not specified, the outstanding balance becomes due on divorce or the husband's death.

For example, if a man and woman agree that the mahr will be $10,000 and it will be paid in two installments, $5,000 at the time of marriage and $5,000 six months later, then the man must pay the agreed amount at the specified times. If he fails to do so, the outstanding balance becomes due on divorce or his death.

It is important to note that although the mahr has a religious basis, secular courts may uphold the agreement if its secular terms are enforceable as a prenuptial contract.

Example: A Muslim couple in the United States agrees that the mahr will be $20,000 and it will be paid in full at the time of marriage. The couple gets divorced after five years, and the husband has only paid $10,000 of the mahr. The outstanding balance of $10,000 becomes due on divorce, and the wife can take legal action to collect the remaining amount.