Taxonomy is one of those words that most people never hear or use. Basically, a taxonomy is a way to group things together.
And a custom taxonomy is a taxonomy with it’s customize settings for example:
For example, you might have a bunch of different types of animals or different type of book categories. You can group them together according to various characteristics and then assign those groups names.
This is something most people encounter in biology classes, and it is known as the Linnaean Taxonomy.
Advanced Custom Taxonomies lets you create your custom taxonomies quick and easy. Below are a few screenshots showing how simple it is and how much control you can have.