The Classical Human CNS - 2019 is the most recent comprehensively segmented, hierarchical model of the Human central nervous system as reconstructed from coronal sections. It is the model most appropriate for neuroscientists for whom grouping structures by proximity (rather than function or embryonic origin for example) is desired...surgeons and users of brain injection and stimulation techniques, for example. The brain component of the 2019 hierarchy is based on the segmentation illustrated in the Gyral Version of the Allen Human brain Atlas (http://atlas.brain-map.org). The spinal cord is identical to the existing Classical Spinal Cord Hierarchy of NeuroNames. The 2019 version is largely the same as the original NeuroNames Hierarchy ( Bowden and Martin, 1995 ). That version, now 25 years old, was itself based on authoritative sources published more than a decade earlier( Nomina Anatomic, 1983; Carpenter, 1983; and Crosby and Humphrey, 1962 ). At higher levels, the Allen hierarchy is the same as that of the 1995 NeuroNames hierarchy. It is different, however, at deeper levels of segmentation, particulary of subcortical forebrain nuclei of the forebrain. substructures of, for example, the thalamus, striatopallidum, and amygdala have been substantially revised in light of better-defined parcellations that have accumulated in decades since the 1980s. The hierarchy of the 2019 version differs from the 1995 version in that gray matter structures, white matter structures, ventricles, and superficial features are grouped at the forebrain, midbrain, and hindbrain levels rather than with the smallest volumetric structures that incorporate them. Insofar as possible the standard terminology remains the same as in the original NeuroNames. For example, where multiple legitimate names apply to the same structure, priority is given to English or anglicized Latin over other languages, e.g., 'midbrain' instead of 'mesencephalon', (Capitalized Latin names are reserved in NeuroNames for reference to their embryonic precursors.), Eponyms and archaic spellings are avoided, e.g., 'subthalamus' and 'locus ceruleus' are used instead of 'nucleus of Luys' and 'locus coeruleus' or 'locus caeruleus'. Grammatically incorrect adjectival endings are avoided, e.g., 'lateral amygdalar nucleus' replaces the older term 'lateral amygdaloid nucleus'. Short is better than long, e.g., 'amygdala' is preferred to 'amygdaloid complex'. And, all other things being equal, the name most frequently applied to a structure, as evidenced by the number of abstracts it retrieves in PubMed, is preferred to names less commonly encountered.