WordPress 4.4 introduced **term meta data** which allows you to save meta values for terms in a similar way to post meta data. This is a highly anticipated and logical addition to the WordPress system.
So far, the post and comment meta systems allowed us to add arbitrary data to posts and comments. This can be used to add ratings to comments, indicate your mood while you were writing a post, attach prices to product posts, and various other information you think is relevant to your content. As of the newest version of WordPress, **meta data can now be added to terms** which allows us to create features like default category thumbnails in a standardized way. This tutorial will show you how you can edit, update and retrieve these meta data for terms.
I add author as a tag to all my book reviews, and would like a way to see all the author tags in one spot. Adding term meta data to the tags sounds like a way to do that.
Added 12/8: David clarified that what I really need is a new taxonomy, so that author name would have its own field instead of being a tag. Then I could add term meta data to that taxonomy if I wanted to track, say, BIPOC or queer authors. Thanks David!