Definition of Scotch boot in English:

Scotch boot

noun

historical
  • An instrument of torture formerly used in Scotland, consisting of a tight-fitting iron case in which a person's leg is enclosed, iron wedges being then driven between the case and the leg; = "boot".

Origin

Early 17th century; earliest use found in John Marston (bap. 1576, d. 1634), poet and playwright.