Definition of boot-up:
(n) :
(footwear) A heavy shoe that covers part of the leg.
(n) :
(sports) A kind of sports shoe worn by players of certain games such as cricket and football (historically in the form of boots, now shorter, but still called the same).
(n) :
(uncountable) A blow with the foot; a kick.
(n) :
(construction) A flexible cover of rubber or plastic, which may be preformed to a particular shape and used to protect a shaft, lever, switch, or opening from dust, dirt, moisture, etc.
(n) :
(figurative, with definite article) Oppression, an oppressor.
(n) :
(usually preceded by definite article) A torture device used on the feet or legs, such as a Spanish boot.