pinnule

[pin-yool]

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.

pinnule

/ 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

pinnule

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.

Other Word Forms

• pinnular adjective

Word History and Origins

Origin of pinnule¹

1585–95; < Latin pinnula pinnula

Word History and Origins

Origin of pinnule¹

C16: from Latin pinnula, diminutive of pinna feather

Example Sentences

The cordate pinnules sometimes found here are commoner in Europe.

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Its value was much impaired by his preference of the antique “pinnules” to telescopic sights on quadrants.

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Arms fork once to thrice, and bear pinnules on each or on every other brachial.

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It is probably a fern, more minute in its pinnules than even our smallest specimens of true maidenhair.

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Ordinary frond and forked and crested varieties of the same, the crest arising from the inordinate development of the margins of the pinnules.

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