protactiniumWiktionary 原文英/ˌprəʊ.tækˈtɪn.i.əm/美/ˌproʊ.tækˈtɪn.i.əm/构词拆解protproto-前缀actiniumactinium词干proto-An early, primitive stage of development. · Original, older.词源说明From proto- + actinium.释义名词noun1(chemistry) A chemical element (symbol Pa) with atomic number 91. A dense, silvery-gray actinide metal.同族词派生词 3diprotactinium·protactinate·eka-protactinium相关词