Why is the ninth month called September?
mid-13c., from Old French cisterne "cistern; dungeon, underground prison" (12c., Modern French citerne), from Latin cisterna "underground reservoir for water," from cista "chest, box," from Greek kiste "box, chest" (see chest).
cistern cis·tern (sĭs'tərn)
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; Prov. 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). (See WELL.) 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.