Lewis & Short

dēductōrĭus, a, um, adj. [deduco], of or for drawing off or draining (post-class.): medicamenta, aperient, purgative, Cael. Aur. Acut. 2, 19: cuniculus (in stabulis), Veg. Vet. 1, 56. Also subst.: deducto-rium, ii, n., a drain: liquoris, Pall. Nov. 7, 21.