Ma'anar ƙamus na kalmar "atom bomb" tana nufin wani nau'in makamin nukiliya wanda ke amfani da makamashin da aka fitar ta hanyar halayen nukiliya wanda ya shafi rarrabuwar (fission) na atomic nuclei don haifar da fashewa mai tsanani. Hakanan aka sani da bam ɗin atomic, A-bam, ko bam ɗin nukiliya, yawanci ya ƙunshi amfani da isotopes na fissile kamar uranium-235 ko plutonium-239 azaman mai. Lokacin da aka haɗa waɗannan isotopes tare a cikin taro mai mahimmanci kuma aka sami hanyar amsa sarkar, suna sakin makamashi mai yawa a cikin nau'in fashewa, suna haifar da lalacewa da lalacewa. Ana ɗaukar bama-bamai na Atom a matsayin ɗaya daga cikin mafi ƙarfi da muggan makamai da aka taɓa ƙirƙira, kuma amfani da su yana da tasiri na ɗabi'a, ɗabi'a, da ɗan adam.