A formidable and reliable power or force; an impregnable stronghold.
在关键时刻，他成为我们团队的铁壁铜山，支撑着大家度过难关。
At critical moments, he became the formidable and reliable force for our team, supporting everyone through the difficulties.
Next Idiom
A formidable and reliable power or force; an impregnable stronghold.