pinnule

American  

[pin-yool] / ˈpɪn yul /

noun

1. Zoology.

   1. a part or organ resembling a barb of a feather, a fin, or the like.

   2. a finlet.

2. Botany. a secondary pinna, one of the pinnately disposed divisions of a bipinnate leaf.

3. a metal plate with a small hole in it, used as a sight in a quadrant.

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pinnule British  

/ ˈpɪnjʊlə, ˈpɪnjuːl /

noun

1. any of the lobes of a leaflet of a pinnate compound leaf, which is itself pinnately divided

2. zoology any feather-like part, such as any of the arms of a sea lily

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pinnule Scientific  

/ pĭn′yo̅o̅l /

1. Any of the smaller leaflets into which each leaflet of a bipinnately compound leaf is subdivided. The leaves of many ferns are divided into pinnules.

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Other Word Forms

• pinnular adjective

Etymology

Origin of pinnule

1585–95; < Latin pinnula pinnula

Example Sentences

Sori on the edge of a pinnule terminating a vein; sporangia at the base of a long, bristle-like receptacle surrounded by a cup-shaped indusium.

From The Fern Lover's Companion A Guide for the Northeastern States and Canada by Tilton, George Henry

The parts of the oak fern develop with great regularity, each pinna, pinnule and lobe having another exactly opposite to it nearly always.

From The Fern Lover's Companion A Guide for the Northeastern States and Canada by Tilton, George Henry

The indusium is formed of the altered margin of the pinnule, at first reflexed to the midrib, giving it a pod-like appearance, but at length opening out flat and exposing the sporangia.

From The Fern Lover's Companion A Guide for the Northeastern States and Canada by Tilton, George Henry

The French pinnule is properly a sight-vane at the end of a traversing bar.

From The Travels of Marco Polo — Volume 1 by Yule, Henry

Pinnules on the inferior side of the pinnæ often elongated, especially the lower pair, the pinnule nearest the rachis being usually the longest, at least in the lowest pinnæ.

From The Fern Lover's Companion A Guide for the Northeastern States and Canada by Tilton, George Henry