Medieval Arabic to Persian dictionaries are a relatively untapped source for the conceptual world in the time of their authors. This essay closely examines four such dictionaries from the late fifth/eleventh century to the seventh/thirteenth century written in eastern Iran. These dictionaries are quite rich in terminology for cities, towns, farmland, pasture and desert. They also describe architectural features of buildings. They offer scant but valuable information on markets and social structure. The information from these dictionaries combined with the rich detail available in the Islamic geographers of the third/ninth and fourth/tenth century allows us to form a more perfect picture of medieval Iranian society.