Facets provide aggregated data based on a search query. Typical examples are tag clouds and faceted navigation, which lets site visitors restrict search results to selected categories such as product types, price ranges, or author names.
Facets are requested and retrieved along with regular search requests. It is important to note that they are scoped for the search query by default.
Elastic Search, upon which EPiServer Find is built, features several facets ranging from simple to advanced, such as Terms, Range, Statistical and Geo Distance. The .NET client API for facets supports Terms, Histogram, Filter, Range and Geographical distance.
Facets and filters
Normally, facets are affected by filters, just like search results. However, via the FilterHits method, it is possible to retrieve facets without applying the filters applied to search results . Therefore, it's good to read up on the Filter and FilterHits methods, because there are significant differences between them when working with facets.