- the most posterior of the three primary divisions of the brain in the embryo of a vertebrate or the part of the adult brain derived from this tissue, including the cerebellum, pons, and medulla oblongata; rhombencephalon.
- the nontechnical name for rhombencephalon
- The rearmost part of the vertebrate brain. In humans, it consists of the pons and the medulla oblongata. Compare forebrain midbrain.