Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
The "bow of steel" in (A.V.) 2 Sam. 22:35; Job 20:24; Ps. 18:34 is in the Revised Version "bow of brass" (Heb.kesheth-nehushah). In Jer. 15:12 the same word is used, and is also rendered in the Revised Version "brass." But more correctly it is copper (q.v.), as brass in the ordinary sense of the word (an alloy of copper and zinc) was not known to the ancients.