Home/protoactiniumprotoactinium/proh-toh-ak-tin-ee-uhm/US // ˌproʊ toʊ ækˈtɪn i əm //UK // (ˌprəʊtəʊækˈtɪnɪəm) //原肠动物,原牙,原肠道,原子能Definitionsn.名词 noun1 Chemistry.: protactinium. Level 5Browse all words →