Classification approach that assigns values for a set of mutually exclusive categories (or facets) to a specific content item in a group of similar objects. For used car listings, such facets would include price, colour, make, model, year, mileage, and location.

Facets allow more flexible classification and navigation — rather than only finding a specific content item through a fixed path (as in a taxonomy) users can browse by the facets that matter the most to them. Facets are often used to refine search queries as well.