A more thorough explanation:

Definition: A cumulative supplement is a small booklet that is added to the back inside cover of a lawbook, such as a treatise or code, to update the information in the main text until a new edition of the entire work is published. Legal publishers often leave extra space in their hardcover books for these supplements.

Example: Let's say you have a lawbook that was published in 2010. Since then, there have been changes to the laws that are covered in the book. Instead of publishing an entirely new edition of the book, the publisher may release a cumulative supplement that includes the updated information. This supplement can be inserted into the back of the book, allowing readers to stay up-to-date without having to purchase a whole new book.

Explanation: The example illustrates how a cumulative supplement is used to update a lawbook without having to publish an entirely new edition. By adding a small booklet to the back of the book, readers can access the most current information without having to purchase a new book. This is a cost-effective way for publishers to keep their books relevant and useful to readers.