Booting the computer is often referred to as starting the computer up.
It is a series of processes or operations that get the computer up and running when it is powered on.
A "cold boot" is when the computer is powered up from the completely off position.
It is not "sleeping" or "hibernating" as some do to conserve energy - the computer is still powered on for both of those processes to occur.
Most users perform a cold boot each morning when they turn on their system for the day.
A "warm boot" is when the computer is restarted, either from the user telling the operating system to restart or from a program that needs the system to restart in order to use it.
There is also a term called a "random boot".
And we do not like when this happens.
A random boot usually happens when there is a software or hardware conflict or problem in the system which makes the computer reboot.
Finding and fixing what caused that to happen is not fun, so thank goodness it is not something that happens regularly.