metacoel
/ˈmɛtəsiːl/(also metacoele)
noun
1 Anatomy and Zoology. In form metacoele. (The caudal part of) the fourth ventricle of the brain. Compare metacoelia rare.
2 Zoology. Usually in form metacoel. The most posterior division of the coelomic cavity of a hemichordate or lophophorate.
Origin
Late 19th century (in an earlier sense). From meta- + -coele. Compare slightly earlier metacoelia.