名詞 counterpart:

1. a person or thing having the same function or characteristics as another
   同義詞：opposite number, vis-a-vis
2. a duplicate copy
   同義詞：similitude, twin

1. Night is the counterpart of day.
   黑夜與白天相輔相成。
2. One that is foreshadowed by or identified with an earlier symbol or type, such as a figure in the New Testament who has a counterpart in the Old Testament.
   先前原形先前的標記或模型所預示或表明的原形，如《新約》中的人物在《舊約》中有對應的形象
3. I racked my memory in vain for its counterpart in literature: perhaps you could think of one.
   我絞盡腦汁也想不出它在文學中的對等物，也許你可以想出一個。

coun.ter.part

n.（名詞）

One that closely resembles another.
相似物：與另一物極相似的東西
One that has the same functions and characteristics as another; an opposite number:
對手方相應的人或物：與另一個具有相同的功能或特點的人或物；對策的人：
例句：
The foreign minister is the counterpart of the secretary of state.
外交部長是和國務秘書對等的人

A copy or duplicate of a legal paper.
復制品，副本：法律文本的復制品或副本

One of two parts that fit and complete each other.
配對物：兩個互相搭配或一體的部分之一
One that serves as a complement.
補充品：作為補充的物或人