I am creating a resource library for students at my online school that will be searchable with metadata. Many sites such as WorldCat have a tool on the left-hand side where you can filter or refine content (look at the div tag "FormatRefinement" in the example) based on metadata.
What is this functionality called? Intuitively, it would seem to be called a 'content filter' but any search for filters brings me to the WordPress Codex where it discusses 'hooks and filters.' I've tried searching for the correct terminology myself but, after several months, no luck. Thank you.