Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
The rendering of a Hebrew word bor, which means a receptacle for water conveyed to it; distinguished from beer, which denotes a place where water rises on the spot (Jer. 2:13; Pr. 5:15; Isa. 36:16), a fountain. Cisterns are frequently mentioned in Scripture. The scarcity of springs in Palestine made it necessary to collect rain-water in reservoirs and cisterns (Num. 21:22).
Empty cisterns were sometimes used as prisons (Jer. 38:6; Lam. 3:53; Ps. 40:2, 69:15). The "pit" into which Joseph was cast (Gen. 37:24) was a beer or dry well. There are numerous remains of ancient cisterns in all parts of Palestine.