codicil

As nouns the difference between addendum and codicil

is that addendum is something to be added; especially text added as an appendix or supplement to a document while codicil is an addition or supplement that explains, modifies, or revokes a will or part of one.

As nouns the difference between prologue and codicil

is that prologue is a speech or section used as an introduction, especially to a play or novel while codicil is (legal) an addition or supplement that explains, modifies, or revokes a will or part of one.

As a verb prologue

is to introduce with a formal preface, or prologue.

As a noun codicil

is (legal) an addition or supplement that explains, modifies, or revokes a will or part of one.

As an adjective codicillary is

of or pertaining to a codicil.