A WordPress taxonomy is a way to organize groups of posts and custom post types.
By default, WordPress comes with two taxonomies called categories and tags. You can use them to organize your blog posts.
However, if you are using a custom post type, then categories and tags may not look suitable for all content.
For instance, you can create a custom post type called ‘Books’ and sort it using a custom taxonomy called ‘topics’.
You can add topic terms like Adventure, Romance, Horror, and other book topics you want. This would allow you, and your readers to easily sort and filter books by each topic.