Pinna

n. pl. Pinnæ (#), E. Pinnas (#).

1. (Bot.) One of the divisions of a pinnate part or organ.
2. (Zoöl.) 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.
3. (Anat.) The auricle of the ear. See Ear.
1. A leaflet of a pinnate leaf. See Illust. of Bipinnate leaf, under Bipinnate.
2. One of the primary divisions of a decompound leaf.