稀有元素

trace element (nutrition)

rare / uncommon / watery / sparse

uncommon

to have; there is / (bound form) having; with; -ful; -ed; -al (as in 有意[you3 yi4] intentional)

surname Yuan / the Yuan or Mongol dynasty (1279-1368)

currency unit (esp. Chinese yuan) / first / original / primary / fundamental / constituent / part / era (of a reign) / meta- (prefix) / (math.) argument / variable / (Tw) (geology) eon

element / element of a set / chemical element

element (key component of sth) / (chemistry) element / (math.) element (member of a set)

raw silk / white / plain, unadorned / vegetarian (food) / essence / nature / element / constituent / usually / always / ever