Pin"na (?), n.; pl. Pinnae (#), E. Pinnas (#). [L., a feather.]
1. Bot. (a)
A leaflet of a pinnate leaf. See Illust. of Bipinnate leaf, under Bipinnate.
(b)
One of the primary divisions of a decompound leaf.
2. Zool.
One of the divisions of a pinnate part or organ.
3. [L. pinna, akin to Gr. .] Zool.
Any species of Pinna, a genus of large bivalve mollusks found in all warm seas. The byssus consists of a large number of long, silky fibers, which have been used in manufacturing woven fabrics, as a curiosity.
4. Anat.
The auricle of the ear. See Ear.
© Webster 1913.