[co.nus ar.te.ri.o.sus] n, pl co.ni ar.te.ri.o.si [NL, lit., arterial cone] (ca. 1860) 1: a conical prolongation of the right ventricle in mammals from which the pulmonary arteries emerge--called also conus
2: a prolongation of the ventricle of amphibians and some fishes that has a spiral valve separating venous blood going to the respiratory arteries from blood going to the aorta and systemic arteries