A prenuptial agreement, antenuptial agreement, or premarital agreement is a written contract entered into by a couple before marriage or a civil union that enables them to select and control many of the legal rights they acquire upon marrying, and what happens when their marriage eventually ends by death or divorce. Couples enter into a written prenuptial agreement to supersede many of the default marital laws that would otherwise apply in the event of divorce, such as the laws that govern the division of property, retirement benefits, savings, and the right to seek alimony with agreed-upon terms that provide certainty and clarify their marital rights. A premarital agreement may also contain waivers of a surviving spouse's right to claim an elective share of the estate of the deceased spouse.