Lewis & Short

Gĕmōnĭae scalae, or (more freq.) absol., Gemoniae, ārum, f. [gemo, cf. "The Bridge of Sighs"], steps on the Aventine Hill leading to the Tiber, to which the bodies of executed criminals were dragged by hooks to be thrown into the Tiber: nemo punitorum non et in Gemonias abjectus uncoque tractus, Suet. Tib. 61: Gemoniae, id. Vit. 17; id. Tib. 53; 75; Juv. 10, 65; Val. Max. 6, 9, 13; Tac. A. 3, 14; 5, 9; 6, 25; id. H. 3, 74; 85; in full: Gemoniae scalae, Val. Max. 6, 3, 3.
Called also: gradus Gemi-torii, Plin. 8, 40, 61, § 145.