Addendum

In the plural, both the Latin "addenda" and the English adaptation "addendums" are acceptable.

Books

In a book, an "addendum" (sometimes referred to as an "appendix") is a supplemental addition to a given main work. It may correct errors, explain inconsistencies or otherwise detail or update the information found in the main work, especially if any such problems were detected too late to correct the main work. For example, the main work could have had already been printed and the cost of destroying the batch and reprinting is deemed too high. As such, addenda may come in many forms — a separate letter included with the work, text files on a digital medium, or any similar carrier.

Addenda can also be used in fictional works to give more detailed information about an idea, history, or technology when incorporating the information into the main text would either slow the story or take away from the author's main idea. Examples of this are found in "The Lord of the Rings" by J.R.R. Tolkien, where the addenda are used to give histories of the characters and nations involved. "Day of the Cheetah" by Dale Brown uses the appendix to explain its fictional technologies in greater detail. In "The Handmaid's Tale" by Margaret Atwood, the appendix presents a frame story, set far in the future from the main body of the novel. A majority of Ursula K. LeGuin's post-apocalyptic book "Always Coming Home" is formed of appendices: songs, legends, recipes, maps, and so on. Addenda of this sort seem particularly prevalent in science fiction, because there is a lot to explain. The Flashman series of pseudo-memoirs depend on addenda masquerading as footnotes to place the fiction within its historic context.

Contracts

In other documents, most importantly in contracts, an addendum is an additional text not included in the main text which may contain additional specifications, provisions, standard forms or other information, especially pricing information. A contract addendum is identical to a contract appendix (addendum is used more commonly)..

Schedules and Exhibits are sub-categories of addenda, with schedules being related to "numerical and time information" such as pricing and time-schedules, and "exhibits" used for examples of "standard forms and different types of evidence or models".

Engineering

The addendum is the height by which a tooth of a gear projects beyond (outside for external, or inside for internal) the standard pitch circle or pitch line; also, the radial distance between the pitch circle and the addendum circle.

ee also

* Appendix
* Postscript