hibakusha UK /ˈhɪbəˌkuːʃə/US /ˌhibəˈkuʃə/ noun1 •A survivor of the 1945 atomic bombings of Hiroshima and Nagasaki.The Treaty on the Prohibition of Nuclear Weapons took effect in January after years of civil effort joined by atomic bombing survivors, or hibakusha. — 2021 formshibakushas