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

/ 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.

Derived Forms

• ˈpinnular, adjective

Other Words From

• pin·nu·lar [pin, -y, uh, -ler], 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

Each pinnule has its edges so much recurved that the whole forms a sort of pouch, apparently filled with sporangia.

From Project Gutenberg

They occur about midway between the central vein of the pinnule and the margin of the leaf.

From Project Gutenberg

The sori are in the form of lines which branch out from the lower part of the pinnule in a fan-shaped manner.

From Project Gutenberg

The sori are placed on small veins which grow outwards from the midrib of the pinnule.

From Project Gutenberg

Sporangia in oblong sori under a reflexed tooth of a pinnule; indusium broad; rachis dark and shining.

From Project Gutenberg