duc·tus ar·te·ri·o·sus 
(dŭktəs är-tîr′ē-ōsəs)
(dŭktəs är-tîr′ē-ōsəs)n.
A fetal blood vessel that connects the left pulmonary artery with the descending aorta and that normally closes at birth.
[Modern Latin : ductus, duct (from Latin, act of leading; see DUCT) + artēriōsus, arterial (from Latin artēria, artery; see ARTERY + -ōsus, adj. suff.)]