Vessel within the umbilical cord, entering the fetus at the umbilicus and carrying oxygenated blood from the placenta.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 817 (https://doi.org/10.1515/pac-2015-1202)