cpu - What is the meaning of the output of the command 'sensors'? - Ask Ubuntu

i have installed package 'lm-sensors' , use command 'sensors' check temperature of cpu. output of command this:

acpitz-virtual-0 adapter: virtual device temp1:        +52.5°c  (crit = +93.0°c)  coretemp-isa-0000 adapter: isa adapter core 0:       +46.0°c  (high = +90.0°c, crit = +90.0°c) core 1:       +48.0°c  (high = +90.0°c, crit = +90.0°c)  dell_smm-virtual-0 adapter: virtual device processor fan: 3000 rpm cpu:            +52.0°c   other:          +44.0°c   other:          +45.0°c  

what virtual mean here? 'isa' , 'acpitz'? 1 real temperature of cpu?

from https://en.wikipedia.org/wiki/system_management_mode:

smm special-purpose operating mode provided handling system-wide functions power management, system hardware control, or proprietary oem designed code.

dell_smm-virtual-0 cpu fan, managed system firmware.

acpitz-virtual-0 temperature sensor near/on cpu socket. sensor can unreliable.

coretemp-isa-0000 measures temperature of specific cores.

if have intel device, cpu sensor , motherboard sensor should generally accurate, or close each other's readings. many amd cpus have faulty onboard sensors heavily conflict motherboard readings.

also, given have laptop, , firmware-controlled fan, a) fan control not possible, , b) cpu temperatures fine.