Brass ceiling is an imaginary barrier which stops women from progressing in their careers within the military and law enforcement.

Brass ceiling（黄铜天花板）指存在于军队和执法部门中、阻止女性进一步升迁的一个无形障碍。

The term is a play on glass ceiling, which refers to the unseen, yet unbreakable barrier that keeps minorities and women from rising to the upper rungs of the corporate ladder, regardless of their qualifications or achievements. The word ‘brass’ here symbolizes the uniform of military and law enforcement officers because traditionally all the buttons in their uniforms are made of brass.

Brass ceiling一词是由glass ceiling（玻璃天花板）演化而来的，后者指不顾资质和成绩，阻碍少数民族和女性在职场升迁的一道无形又难以打破的障碍。这里的brass一词就代表军队和执法部门的制服，因为他们的制服纽扣都是用黄铜做的。

For example:

The appointment of the first woman to command the Air Force Academy marks another breach of the "brass ceiling" that keeps women from top assignments in the military.

首次任命女性统领空军学院标志着对黄铜天花板的又一次破击，黄铜天花板阻止女性在军中担任要职。