cod·i·cil / ˈkädəsəl; -ˌsil/ • n. an addition or supplement that explains, modifies, or revokes a will or part of one. DERIVATIVES: cod·i·cil·la·ry / ˌkädəˈsilərē/ adj.
A document that is executed by a person who had previously made his or her will, to modify, delete, qualify, or revoke provisions contained in it.
A codicil effectuates a change in an existing will without requiring that the will be reexecuted. The maker of the codicil identifies the will that is to be changed by the date of its execution. The codicil should state that the will is affirmed except for the changes contained therein. The same formalities that are necessary for the valid execution of a will must be observed when a codicil is executed. Failure to do so renders the codicil void.