A visitor is classed as a monthly active user across all properties. It does not take into account page views.
Monthly Unique Visitors (MUV) are visitors that view your social proof tools (ReviewHQ, widgets, FOMO popups and/or Wall of Love) on your website(s) per month. The platform tracks the IP address of each visitor and new IP address visits for the current month are unique. If a visitor from the same IP address returns more than once in the current month, after the first visit they are no longer counted towards the Monthly Unique Visitors count.