·add. ·adj Of, pertaining to, or named from, the Neanderthal, a valley in the Rhine Province, in which were found parts of a skeleton of an early type of man. The skull is characterized by extreme dolichocephaly, flat, retreating forehead, with closed frontal sutures, and enormous superciliary ridges. The cranial capacity is estimated at about 1,220 cubic centimeters, being about midway between that of the Pithecanthropus and modern man. Hence, designating the Neanderthal race, / man, a species supposed to have been widespread in paleolithic Europe.