trispastos
From LSJ
trispastos: i, f. (sc. machina), = τρίσπαστος,>
I a hoisting-tackle with three pulleys, two in the upper and one in the lower block, a trispast, Vitr. 10, 3.
trispastŏs, ī, f. (τρίσπαστος), machine à trois poulies : Vitr. Arch. 10, 2, 3.