The definition for uptime is "Tell how long the system has been running." but if you change your system power state to suspend or resume:
# uptime
09:50:33 up 8 min, 2 users, load average: 0,24, 0,33, 0,15
# pm-suspend
(5 minutes later, turning on again)
# uptime
09:55:15 up 13 min, 2 users, load average: 0,33, 0,33, 0,16
# pm-hibernate
(5 minutes later, turning on again)
# uptime
10:01:16 up 19 min, 2 users, load average: 3,77, 1,14, 0,43
The system hasn't been running but the uptime time counter increases.
Using the term "wall time" or "elapsed real time" in their definition instead of "has been running" can be the right approach nowadays?