What does Boot menu mean?

Boot menu meaning in Computer Science Dictionary

whenever a computer is starting up, a person have access to the boot selection by pushing one of several keyboard keys, including Esc, F10 or F12, depending on the manufacturer regarding the computer system or motherboard. The particular key to hit is normally specified on the computer's startup screen. The boot selection enables a user to select what product to load an operating system or application from since the computer is booting.