eka-actiniumWiktionary 原文英美构词拆解eka-前缀+actinium词干eka-(chemistry) Used to form prototype names for as-yet undiscovered elements, when prepended to the known element above them in the same group of the periodic table.词源说明From eka- + actinium.释义名词noun1(chemistry) unbiunium (element 121)2(chemistry) untriennium (dvi-lanthanum) (element 139)