A bomb is an explosive object that makes and lets out its energy very quickly. This detonation makes a big shock wave. Bombs have been used for centuries. Some bombs also throw out dangerous metal fragments, and some are firebombs.
A bomb is usually some kind of container filled with explosive material that is designed to destroy things. The word bomb comes from the Greek word βόμβος (bombas), an onomatopoeic term with almost the same meaning as "boom" in English.