• WordNet 3.6
    • n pinnule division of a usually pinnately divided leaf
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Webster's Revised Unabridged Dictionary
    • Pinnule (Zoöl) Any one of a series of small, slender organs, or parts, when arranged in rows so as to have a plumelike appearance; as, a pinnule of a gorgonia; the pinnules of a crinoid.
    • Pinnule (Bot) One of the small divisions of a decompound frond or leaf. See Illust. of Bipinnate leaf, under Bipinnate.
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Century Dictionary and Cyclopedia
    • n pinnule A pinnula.
    • n pinnule In ichthyology, specifically, a small fin-like appendage. It is developed especially in scombroid fishes, as the mackerel, behind the dorsal and anal fins. Pinnules are really low, short, detached fin-rays, much branched and without membranous connection with one another or with the fin proper. See cut under mackerel.
    • n pinnule In botany, a secondary pinna; one of the pinnately disposed divisions of a pinna: noting especially the ultimate divisions of the frond in ferns. Also pinnula. See cuts under indusium and Nothochlæna.
    • n pinnule A small pin fixed upon a pre-telescopic astronomical instrument and serving, like the sight of a gun, to enable the observer to make an accurate pointing upon a star or other celestial object.
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Chambers's Twentieth Century Dictionary
    • n Pinnule one of the branchlets of a pinnate leaf: one of the lateral divisions of the finger-like stalks of an encrinite—also Pinn′ūla
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Webster's Revised Unabridged Dictionary
L. pinnula, dim. of pinna, feather: cf. F. pinnule,
Chambers's Twentieth Century Dictionary
L. pinna, a feather, dim. pinnula.


In literature:

These divisions of the pinnae are called pinnules.
"The Fern Lover's Companion" by George Henry Tilton
Branches simple, 2 to 3 inches long; pinnules about 1/4 inch.
"Narrative Of The Voyage Of H.M.S. Rattlesnake, Commanded By The Late Captain Owen Stanley, R.N., F.R.S. Etc. During The Years 1846-1850. Including Discoveries And Surveys In New Guinea, The Louisiade Archipelago, Etc. To Which Is Added The Account Of Mr. E.B. Kennedy's Expedition For The Exploration Of The Cape York Peninsula. By John Macgillivray, F.R.G.S. Naturalist To The Expedition. In Two Volumes. Volume 1." by John MacGillivray
All the Palaeozoic representatives have non-pinnulate arms, while the Mesozoic and later forms have them pinnulate.
"Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10" by Various
Its value was much impaired by his preference of the antique "pinnules" to telescopic sights on quadrants.
"Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4" by Various
Midrib of the pinnules marginal or none.
"The Manual of the Botany of the Northern United States" by Asa Gray