columella

n. [ L., dim. of columen column. See Column. ] 1. (Bot.) (a) An axis to which a carpel of a compound pistil may be attached, as in the case of the geranium; or which is left when a pod opens. (b)A columnlike axis in the capsules of mosses. [ 1913 Webster ]

2. (Anat.) A term applied to various columnlike parts; as, the columella, or epipterygoid bone, in the skull of many lizards; the columella of the ear, the bony or cartilaginous rod connecting the tympanic membrane with the internal ear. [ 1913 Webster ]

3. (Zool.) (a) The upright pillar in the axis of most univalve shells. (b) The central pillar or axis of the calicles of certain corals. [ 1913 Webster ]