pinnule

[ pin-yool ]

noun
  1. Zoology.

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

    • a finlet.

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

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

Origin of pinnule

1
1585–95; <Latin pinnulapinnula

Other words from pinnule

  • pin·nu·lar [pin-yuh-ler], /ˈpɪn yə lər/, adjective

Words Nearby pinnule

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use pinnule in a sentence

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

    Beautiful Ferns | Daniel Cady Eaton
  • They occur about midway between the central vein of the pinnule and the margin of the leaf.

    How to Know the Ferns | S. Leonard Bastin
  • The sori are in the form of lines which branch out from the lower part of the pinnule in a fan-shaped manner.

    How to Know the Ferns | S. Leonard Bastin
  • The sori are placed on small veins which grow outwards from the midrib of the pinnule.

    How to Know the Ferns | S. Leonard Bastin
  • 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

British Dictionary definitions for pinnule

pinnule

pinnula (ˈpɪnjʊlə)

/ (ˈpɪnjuːl) /


nounplural pinnules or pinnulae (ˈpɪnjʊˌliː)
  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

Origin of pinnule

1
C16: from Latin pinnula, diminutive of pinna feather

Derived forms of pinnule

  • pinnular, adjective

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

Scientific definitions for pinnule

pinnule

[ pĭnyōōl ]


  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.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.