Use category visibility to control which categories are publicly viewable.

Category Visibility

Categorizing your entities allows you to group entities in a meaningful way to your organization. In some cases these categorizations may be for public usage, such as filtering sessions by category on the Event Site. However, sometimes you may want to categorize your entities for internal usage. Depending on your needs, Grenadine offers two visibilities for categories: Public and Organizer. Categories with Public visibility will be shown on the Event Site for the relevant entities that display categories on the site. Organizer visibility categories will not appear on the Event Site and will only be seen on the Manager.