pinnule definition by Webster's New World
- any of the smallest divisions of a leaf which is doubly compound, esp. in ferns
- any of the lateral branches of the arm of a crinoid
Origin: Modern Latin pinnula ; from Classical Latin diminutive of pinna, wing, feather: see pen
pinnule definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
also pin·nu·lanoun pl. pin·nules also pin·nu·lae
- Botany Any of the ultimate leaflets of a bipinnately compound leaf.
- Zoology A featherlike or plumelike organ or part, such as a small fin, or one of the appendages of a crinoid.
Origin: Latin pinnula, diminutive of pinna, feather; see pet- in Indo-European roots.
- pinˈnu·lar adjective
pinnule - Science Definition
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.