Priesthood, in most religions, refers to one of two functions. A priest either serves the spiritual needs of a particular community, or bears the responsibility for a particular shrine or deity. Of course, some priests have both roles at the same time.
Wicca fits more into the second category, if you think of it as an initiatory priesthood of devotees to the mother goddess and the horned god. A Wiccan high priestess also serves in the first role, by ministering to the spiritual needs of the coven community.
Priesthood in other neopagan and heathen religions is more likely to be of the “community” kind, but there are also “solitary priests.” A solitary priest is a pagan worshiper so devoted to a particular deity that he or she functions as a “shrine priest” of that deity, regardless of the lack of a community around that shrine. Some pagans have expressed a great deal of skepticism about the role of a solitary priest, because they see priesthood as being defined by service to a community. However, both priestly roles can claim historical precedent, so it seems that it is equally legitimate to be the priest of a community or the priest of a specific deity or shrine.