something that looks exactly the same as another thing but with its left and right sides in opposite positions

His home is two terraced houses knocked together, each the mirror image of the other. 他家的房子是两栋相接的连排房子，两座房子完全对称。

a person or object that is very similar to another

The current economic situation is a mirror image of the situation just a few years ago. 目前的经济形势完全是几年前情况的翻版。