noun
: the condition in which a radioactive species and its successive radioactive products have attained such relative proportions that they all disintegrate at the same numerical rate and therefore maintain their proportions constant
noun
: the condition in which a radioactive species and its successive radioactive products have attained such relative proportions that they all disintegrate at the same numerical rate and therefore maintain their proportions constant
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012