This article covers a Bloomreach Experience Manager version 13. There's anupdated version available that covers our most recent release.
Taxonomy Plugin
Introduction
Editors can enrich their metadata using the Taxonomy plugin to categorize the content. The CMS administrator can edit the taxonomy itself.
Screenshots
Taxonomy editor
This is how a taxonomy is edited within the CMS.

Choose terms
After a taxonomy is created, items can be selected from the taxonomy picker.

Taxonomy terms in editor
Selected taxonomy items are shown in the document editor.

Source Code and Demo
https://code.onehippo.org/cms-community/hippo-plugin-taxonomy