• Webster's Revised Unabridged Dictionary
    • a Pinniform Shaped like a fin or feather.
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Century Dictionary and Cyclopedia
    • pinniform Like a feather; penniform.
    • pinniform Like a fin or flipper: as, the pinniform wing of the penguin.
    • pinniform Pinnate in form, in any sense; alate; lobate; auriculate.
    • pinniform Resembling a mollusk of the genus Pinna.
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Chambers's Twentieth Century Dictionary
    • Pinniform like a feather or fin: pinnate
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Webster's Revised Unabridged Dictionary
L. pinna, feather, fin + -form,
Chambers's Twentieth Century Dictionary
L. pinna, a feather, dim. pinnula.