化学需氧量

chemical oxygen demand (an environmental indicator)

variant of 花[hua1]

to make into / to change into / -ization / to ... -ize / to transform / abbr. for 化學|化学[hua4 xue2]

chemistry / chemical

to learn / to study / to imitate / science / -ology

to require / to need / to want / necessity / need

oxygen (chemistry)

to measure

capacity / quantity / amount / to estimate / abbr. for 量詞|量词[liang4 ci2], classifier (in Chinese grammar) / measure word