A session is defined by analytics tools as a group of interactions one user takes within a given time frame on your website. Google Analytics defaults that time frame to 30 minutes, whatever a user does on your website before they leave equals one session. A session is a container for the actions a user takes on your site. Session can contain multiple page views, event, social interactions, and e-commerce transactions. A session ends two different ways: either by time based expiration or a campaign change (user arrives via one campaign, leaves, and returns via a different campaign).