However, your institution may elect to define categories differently.  Many institutions use categories to apply cohorts of students to the lists feature, institutions include cohorts such as extra-curricular activities.  This solely depends on how you have your students currently grouped in your Student Information System.

You may see categories on your homepage, if you have students assigned to you, the Advanced Search page when viewing your search results, and on numerous reports found under the Reports page.  If you have access to the Advanced Search page then you will also be able to search for students by their defined category.