noun, plural ne·en·ceph·a·lons, ne·en·ceph·a·la [nee-en-sef–uh-luh] /ˌni ɛnˈsɛf ə lə/.
- the more recent part of the brain in the evolutionary development of animals, including the cerebral cortex and its related structures.
noun, plural ne·en·ceph·a·lons, ne·en·ceph·a·la [nee-en-sef–uh-luh] /ˌni ɛnˈsɛf ə lə/.