ボール爆ばく弾だんボールばくだんMeanings1nounball bombA spherical explosive device; the term is straightforward and used in military or historical contexts.ボール爆ばく弾だんは第だい二に次じ世せ界かい大たい戦せん中ちゅうに使し用ようされた。Ball bombs were used during World War II.