In carpentry, an upright post or beam supporting the apex of a triangular truss, and resting on the center of a beam which forms the base of the triangle: used esp. in a truss, called king truss, formed by two rafters of a roof and the horizontal tiebeam.

【建】雄柱；中柱。

In an airplane, a similarly placed post bracing a wing.

(飞机上的)主柱。