A winch or lifting device incorporating a system of several pulleys. Also (Surgery): †an apparatus for reducing a dislocated joint (obsolete).
In later use only with reference to the machine described by Vitruvius.
Mid 17th century; earliest use found in John Wilkins (1614–1672), theologian and natural philosopher. From classical Latin polyspaston compound pulley (Vitruvius), in post-classical Latin also an apparatus for reducing a dislocated joint from Hellenistic Greek πολύσπαστον compound pulley, use as noun of neuter of πολύσπαστος drawn by many cords from ancient Greek πολυ- + σπᾶν to draw + -τος, suffix forming verbal adjectives.