a building's air/heating/ventilation 'ducts'
the bile 'duct'
tear 'ducts'
(..) Yeah. SETH: Why do people cry? MAGGIE: What do you mean? I mean, what happens physically? Well. Tear ducts operate on a normal basis to lubricate and protect the eye. When you have an emotion, they overact and create tears. Why? Why do they overact? I don't know. (..)1998 City of Angels