- a part or organ resembling a barb of a feather, a fin, or the like.
- a finlet.
- Botany. a secondary pinna, one of the pinnately disposed divisions of a bipinnate leaf.
- a metal plate with a small hole in it, used as a sight in a quadrant.
Origin of pinnule
1585–95; < Latin pinnula pinnula
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for pinnule
The index reference for "Pinnule" should probably be 59, rather than 66, but was not changed.
Pinnule, a secondary division of a bipinnate or tripinnate leaf, 66.
Sporangia in oblong sori under a reflexed tooth of a pinnule; indusium broad; rachis dark and shining.The Fern Lover's Companion
George Henry Tilton
The sori are placed on small veins which grow outwards from the midrib of the pinnule.
They occur about midway between the central vein of the pinnule and the margin of the leaf.
- any of the lobes of a leaflet of a pinnate compound leaf, which is itself pinnately divided
- zoology any feather-like part, such as any of the arms of a sea lily
C16: from Latin pinnula, diminutive of pinna feather
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- 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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.