(Botany)a structure resembling a small column, typically forming a central axis, in particular (生)小柱;柱 ■(Zoology)the axis of a spiral shell (动)(螺的)轴柱;壳轴 ■(Zoology)an ossicle of the middle ear of birds, reptiles, and amphibians (动)耳柱骨(鸟类、爬虫类和两栖类中耳的小骨) ■(Anatomy)the pillar around which the cochlea spirals (剖)蜗轴,耳蜗的中轴 ■(Botany)the axis of the spore-producing body of some lower plants (植)囊轴;蒴轴;中柱;基粒棒