Written by Thomas Godwin
Updated: May 4, 2023
Image Credit © Reddogs/


The pinna is simply another name (a scientific name, if you will), for the outer ear. The term applies to human ears, along with any animal that has an external ear formation. Of course, like many words, regardless of the language, pinna also has other meanings—a genus of mollusks, and a portion of a compound leaf (in terms of plants).

Pinna (Outer Ear)

While pinna refers to the outer ear, its mostly used in reference to the acoustic qualities of the outer ear. It’s responsible for sound localization in both human beings and most types of animals. That’s because the outer ear is responsible for resonance and amplification. It captures the incoming sound and transmits that sound to the tympanic membrane, which is part of the middle ear.

Genus of Mollusks

A mollusk’s pinna is similar to a human pinna, except it doesn’t have anything to do with hearing. As the external ear in a human or animal is basically a flap of skin and cartilage, the pinna is a flap of mantle tissue that protects the gills in certain mollusks.

Also, like humans, mollusks typically have two pinnas, one for each side of the mollusk’s body. A pen shell mollusk is a good example when it comes to pinna observation since they are extensive in size. In fact, the pinnas on pen shell mollusks are sought after by collectors because they are beautiful and feature a variety of shapes and intricate details.

Pinna (Plants)

In plants, the term pinna is used to describe parts of a larger, compound leaf. A fern is a primary example. The tiny leaves that run on either side of each stem are often referred to as pinnas. Acacias and palms are two more plants where the pinna term applies.

Compound leaves are leaves that make up more than a single leaf on a single petiole. Since ferns, palms, and acacias feature a lot of leaves on a single petiole, they make excellent examples for describing the pinna in botanical terms.

Pinna Pronunciation

Pinna is pronounced: “pi-ne”

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About the Author

Thomas is a freelance writer with an affinity for the great outdoors and Doberman Pinschers. When he's not sitting behind the computer, pounding out stories on black bears and reindeer, he's spending time with his family, two Dobermans (Ares and Athena), and a Ragdoll cat named Heimdal. He also tends his Appleyard Ducks and a variety of overly curious and occasionally vexatious chickens.