Help Information:

Summary
The Summary shows totals and averages for Sessions, Pageviews, Hits, and Bytes for the currently selected Date Range. Visitors information is not shown here because it is only available when UTM visitor tracking is employed.

Calculation Methodology

• Session: A series of Hits to your site over a specific period of time by one visitor.
• Pageview: A request to the web server by a visitor's browser for any web page; this excludes images, javascript, and other generally embedded file types.
• Hit: Any successful request to a webserver from a visitor's browser.
• Bytes: The quantity of network bandwidth used by the files requested during the selected Date Range.

Note
Because Bytes numbers can be very large, abbreviations are used as appropriate, such as MB for megabytes (~millions of bytes). The average length of Session is displayed as hours:minutes:seconds.

 Urchin Documentation Center (help.urchin.com)    Glossary of Terms