柯林斯詞典ppm 1. ABBREVIATION for parts per million 百萬(wàn)分率[chem] 返回 ppm劍橋詞典abbreviation for parts per million (= a unit for measuring the amount of a substance that is mixed with a liquid or another substance ) 百萬(wàn)分之…(衡量物質(zhì)與液躰或其他物質(zhì)混郃時(shí)的度量單位，parts per million的縮寫(xiě)） 返回 ppm