User session
From DigitalJargonBuster
A user session is someone with a unique address that enters or re-enters a website each day (or some other specified period). A user session is sometimes determined by counting only those users that haven't re-entered the site within the past 20 minutes or a similar period. User session figures are sometimes used, somewhat incorrectly, to indicate "visits" or "visitors" per day. User sessions are a better indicator of total site activity than "unique visitors" since they indicate frequency of use.