The Novelist slug is what appears in the URLs of your books. By default the slug is set to ‘books’ which will create URLs like this:
You can use this constant to change the slug to something else.
Place this code in your theme’s functions.php file or in a custom plugin:
define( 'NOVELIST_SLUG', 'your-custom-slug-here' );
To complete the change, go to Settings > Permalinks and re-save your settings.