constituent
noun [ C ] uk/kənˈstɪtʃ.u.ənt/ us/kənˈstɪtʃ.u.ənt/
(PART)
成分;构成部分;要素
one of the parts that a substance or combination is made of
What are the basic constituents of the mixture? 这种混合物的基本成分是什么？
(PERSON)
（某选区的）选民，选举人
a voter (= person who can vote) in a particular area of the country
The MP worked hard, always talking to his constituents and listening to their problems. 这位参议员工作努力，总是跟本区选民交谈，听取他们的难处。