Uptime is the amount of time (in days, hours, and minutes) the server, network, or website has been running (up).  This is usually listed as a percentage, like 99.9% uptime for a given period of time. 

View the uptime for a server, network, or website displayed as Availability above the Events Timeline section in the web client.

System uptime is the duration (in days, hours, and minutes) that the system has remained operational. To view uptime, navigate to Server > click on any server > Summary > System Statistics > Uptime.