"explosive projectile," originally consisting of a hollow ball or shell filled with explosive material, 1580s, from French bombe, from Italian bomba, probably from Latin bombus "a deep, hollow noise; a buzzing or booming sound," from Greek bombos "deep and hollow sound," echoic. Thus probably so called for the sound it makes. Originally of mortar shells, etc.; modern sense of "explosive device placed by hand or dropped from airplane" is from 1909. Meaning "old car" is from 1953. Meaning "success" is from 1954 (late 1990s slang the bomb "the best" probably is a fresh formation); opposite sense of "a failure" is from 1961. The bomb "atomic bomb" is from 1945. Compare shell (n.).