柯林斯詞典trace element (trace elements) 1. N-COUNT A trace element is a chemical element such as iron or zinc that occurs in very small amounts in living things and is necessary for normal growth and development. 痕量元素2. N-COUNT A trace element is a very small amount of a chemical element that is found in a metal or other substance. 微量元素 返回 trace element劍橋詞典one of several types of simple chemical substance that are necessary for healthy growth and development , and exist in animals and plants in very small amounts 微量元素 返回 trace element