korok dissect the physical and social environments into units of considerable significance to both farmers and herders. The substance of this paper will be presented by way of an examination of these units and their variable contents. In my conclusions I relate the korok to an important aspect of Pokot cultural behavior-the interdependence of farmers and herders, and the sense of ethnic unity which both display. Since Schneider (1953, 1957, 1959) recently has described the economy and environment of the Pokot in some detail, only a summary description is needed here of the region in which fieldwork was carried out-West Pokot District of Kenya, an area of some 2,200 square miles, and inhabited by about 60,000 Pokot. As Dr. Porter has emphasized in his paper for this symposium, the physical environment of the District is marked not only by great contraststhe interpenetration of mountains and plains-but by abrupt transitions between the two. Within a short horizontal distance one may pass from highland moors at more than 10,000 feet to semi-arid plains at less than 3,000 feet above sea level, a transition involving great and sudden differences of environmental potentials. The areas of fieldwork approached the extremes of the Pokot environment: about six months were spent with the pastoralists of Masol, in the northern part of the District, where plant cover varies from lush grassland to thorny scrub and hummocked grass. Another six months were spent in Tamkal, a mountain valley south of the Masol plains. In Tamkal, the inhabitants cultivate millets, sorghum, and maize, at times utilizing a network of irrigation canals to distribute water from points of permanent supply to less favored areas in the valley. My informants, although drawn largely from Masol and Tamkal, also included persons from nearly every other part of the District, specifically including the central mountain massif and the western and eastern plains. The responses of these informants, as well as considerable textual material, assert a wide currency of the term korok, and an impressive consensus on the meaning-contents and grammatical status of the term.' Korok has three regular meanings, the first of which is anatomical, and refers to the human tibia or