pinn(i)- Also pinnati-.
Wings, fins, or feathers.
[Latin pinna, penna, wing, fin, feather.]
A leaf that is pinnate has leaflets arranged on either side of the stem, typically in pairs opposite each other, rather like the barbs of a feather; one that is pinnatifid (Latin fid-, cleft) is pinnately divided, but not all the way down to the central axis, as opposed to a pinnatisect one, which is so divided; a pinniped (Latin pes, ped-, foot) is a member of a group of aquatic mammals—the seals, sea lions, and walrus—which have flipper-like limbs. Pinna itself is variously used in technical English to refer to the external part of the ear in humans and other mammals (figuratively the ‘wing’ of the ear), or a primary division of a pinnate leaf, or one of a number of animal structures resembling fins or wings.