Will: A written document in which a person determines how their estate will be handled after his/her death.  Without a valid, legally binding will to direct the management of an estate, it becomes the responsibility of the state to determine the final dispersion of the estate.  A will is a legal instrument that gives a person the ability to choose their heirs, decide which person will best serve as an executor of the estate and select a guardian for young children in the event of his/her death.