Real Dictionary

boot
countable noun: Boots are shoes that cover your whole foot and the lower part of your leg.
countable noun: Boots are strong, heavy shoes which cover your ankle and which have thick soles. You wear them to protect your feet, for example when you are walking or taking part in sport.
countable noun: The boot of a car is a covered space at the back or front, in which you carry things such as luggage and shopping.
verb: If you boot something such as a ball, you kick it hard.

boot in American English 1
noun: a covering of leather, rubber, or the like, for the foot and all or part of the leg

boot in American English 2
noun: something given into the bargain

boot in American English 3
noun: booty; spoil; plunder

boot in Automotive Engineering
noun: A boot is a thin, flexible tube, often shaped like a concertina, that stops dirt and liquids from entering the mechanical parts of a vehicle, such as shaft couplings.

boot in British English 2
to be of advantage or use to (a person)
noun: an advantage