uptime
Reading the systemPackage: procps
How long the machine has been up, and the three load averages. -p keeps the uptime alone, spelled out in words. A reboot nobody asked for shows up here first: a few minutes of uptime on a production server is an incident, not a fact.
What its options do in the lessons
From the same glossary the lessons render under their commands, so the two cannot disagree.
uptime -p- Prints the uptime in plain words —
up 4 days, 8 hours, 11 minutes— without the clock, the user count or the load averages.