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Related to pinnule: pinnation


 (pĭn′yo͞ol) also pin·nu·la (pĭn′yə-lə)
n. pl. pin·nules also pin·nu·lae (pĭn′yə-lē′)
1. Botany One of the secondary divisions of a binnately compound leaf.
2. Zoology A small featherlike part or subdivision of an appendage, especially one of the small branches on the arm of a crinoid.

[Latin pinnula, diminutive of pinna, feather; see pet- in Indo-European roots.]

pin′nu·lar adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ˈpɪnjuːl) or


n, pl pinnules or pinnulae (ˈpɪnjʊˌliː)
1. (Botany) any of the lobes of a leaflet of a pinnate compound leaf, which is itself pinnately divided
2. (Zoology) zoology any feather-like part, such as any of the arms of a sea lily
[C16: from Latin pinnula, diminutive of pinna feather]
ˈpinnular adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈpɪn yul)

1. a part or organ resembling a barb of a feather, a fin, or the like.
2. a secondary pinna, one of the pinnately disposed divisions of a bipinnate leaf.
[1585–95; < Latin pinnula, diminutive of pinna feather; see -ule]
pin′nu•lar (-yə lər) adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.pinnule - division of a usually pinnately divided leafpinnule - division of a usually pinnately divided leaf
leaflet - part of a compound leaf
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
The quantification of galls per pinnule was made from 20 samples, which were obtained from 12 plant individuals at the study site.
A 3 mm X 5 mm square leaf sample was sectioned from the centre of a pinnule (leaflet) (between the midrib and the pinnule margin) collected from a central pinna.
Of these, most are attached to fragmentary, ultimate pinnae (Halle 1927, 1933; Arnold 1937; Zodrow and McCandlish 1980b) without pinnule replacement, or to fragmentary axes (Drinnan et al.
1) on the basis of the overall morphology, size and pinnule shape and despite the indistinct venation.
A particularly conspicuous feature of many scrambling/climbing pteridosperms is marginal thickenings of the lateral pinnule veins (e.g., in Blanzyopteris praedentata, Lescuropteris genuina, Mariopteris occidentalis [Fig.
11a illustrates yet another atypical foliar form, haired, by its comparatively narrow, long and linear pinnule, without basal orbicular pinnules, and with a conspicuous acuminate tip.
Venation of pinnule or ultimate axis: 0 = not anastomosing; 1 = anastomosing.
In a quantitative analysis of pinnule formation in Adiantum and Cheilanthes, mitotic rates were compared for different developing leaf sectors (Zurakowski & Gifford, 1988).
Caulerpa cupressoides (Figure 1A) is characterized by a creeping axis fixed to the substrate by rhizoids pinnules arranged in the opposite direction, endowed with erect shoots (assimilative) pine tree-shaped distributed around the main axis (TRI, 2009).