What Does Boot Up Mean?
To boot up is to start up a computer system by providing it with the required electrical power and loading the startup services until the operating system is loaded. It refers to the process of starting a computer from a dead or offline state, thus making it available to perform any computing operation.
Booting up can also be called boot, booting, bootstrapping and system startup.
Techopedia Explains Boot Up
The boot up process primarily starts when the power button on a CPU or computer system is manually pressed by a human operator. The computer is then activated and performs a series of boot time tests and checks before normal operations can be performed by the user. These checks include the power on self test (POST), which ensures that the computer has enough electrical power to proceed, a peripheral devices check and the initiation of the boot loader, which loads and executes the startup sequence and the operating system.