What exactly are these acpi thermal zone ?

[rsutoratosu]

ACPI thermal zone ACPI\ThermalZone\THRM has been enumerated

I have a laptop that randomly gets that in the event, is it really a thermal event ?

 

[Modelworks]

Chips used for things like fan control have an internal structure that allows them to be set up so that zone 1 might be ram+cache, zone 2 cpu, zone 3 video card. Pretty much the way you can divide a home into zones for heating and cooling.

Usually it means that the temperature exceeded whatever the factory preset was and it triggered another event. What that event is that is triggered can be power reduction to cool the cpu or speeding up the fan.