放ほう射しゃ性せい核かく種しゅほうしゃせいかくしゅMeanings1nounradionuclide; radioactive nuclidephysics›Technical term in nuclear physics and radiochemistry. Refers to an atom with an unstable nucleus that undergoes radioactive decay.放ほう射しゃ性せい核かく種しゅの半はん減