Boot

   To start up the computer or operating system. The term "boot"
is a contraction of "bootstrap", which in turn comes from the
expression "to lift oneself by one's boot straps."  The ROM BIOS on IBM
PCs and compatibles reads in the first sector of the disk, which
contains a short (less than 500 bytes) program that reads in a portion
of the operating system, which in turn reads in the remainder of the
operating system.