from
The Collaborative International Dictionary of English v.0.48
Columella \Col`u*mel"la\, 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]