Facets are groups of attributes users will filter by when looking for a Directory Item(s). Each Facet type should be made up of at least 2 Facets, each of which can apply to 1 or more Directory Items.

As an example, when searching for a school, there are a variety of attributes (Facets) which users will be interested in when looking for one that fits their needs. This is illustrated well by Croydon's Secondary school Directory:

Not all Facet types are made up of mutually-exclusive Facets. In the case of gender most schools are applicable to both Girls and Boys where as other schools are only applicable to one gender.

There are also often cases where Facets will be mutually exclusive such the maximum length of stay for car parks:

Maximum stay (Directory Facet type):

• 1 hour (Directory facet)
• 2 hours (Directory facet)
• 4 hours (Directory facet)
• 6 hours (Directory facet)