Booting
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From the term bootstrapping, or to make complex stuff from simple stuff, booting is when a computer starts up.
[edit] More detail
When you boot a computer, your processor looks in system ROM (the BIOS) for instructions and does them. They normally 'wake up' add-in cards and searches for the boot device. The boot device either loads the operating system or gets the operating system from somplace else.
Now people use the word "boot" to mean "to start a computer" or other device with electronics built in. Most operating systems call the first device it uses a boot device. This is because the computer is making itself go, as in the idiom. When we start a computer, we can often see the simple instructions the computer uses to start, then more complicated pictures or software.
So "to boot" in this meaning is short for "to bootstrap". This use is part of net jargon along with similar multi-use words like net or web. Often the computer is just called a box, so a phrase like "to boot the box" means "to start the computer".
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