Whilst many of the people on this list (myself included) have a pretty good grasp of what is meant by the term facet, this is not clear to people who approach the system from a more fresh point of view.
So, has anyone got a good example of the language they might use over, say, a set of radio buttons and fields on a web form, to indicate that selecting one or more of these would return facets. 'Show grouping by' or 'List the sets that the results fall into' or something similar. Ben