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n. pl. glo·chid·i·a (-ē-ə)
The parasitic larva of most freshwater mussels, having hooks for attaching to the gills or other external parts of a host fish.

[New Latin glōchidium : Greek glōkhīs, barb of an arrow + Latin -idium, diminutive suff. (from Greek -idion).]
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.


n, pl -chidia (-ˈkɪdɪə)
1. (Botany) Also called: glochid a barbed hair, esp among the spore masses of water ferns and on certain other plants
2. (Zoology) a parasitic larva of certain freshwater mussels that attaches itself to the fins or gills of fish by hooks or suckers
[C19: from New Latin, from Greek glōkhis projecting point]
gloˈchidiate adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(gloʊˈkɪd i əm)

n., pl. -chid•i•a (-ˈkɪd i ə)
1. a short hair, bristle, or spine having a barbed tip.
2. the larva of a freshwater mussel of the family Unionidae: a parasite of fishes.
[1895–1900; < New Latin < Greek glōch(ís) point of an arrow]
glo•chid′i•al, 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.glochidium - a barbed spine or bristle (often tufted on cacti)glochidium - a barbed spine or bristle (often tufted on cacti)
pricker, prickle, spikelet, sticker, thorn, spine - a small sharp-pointed tip resembling a spike on a stem or leaf
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
We met, talked, and I eventually began to work with him on this larval stage called a glochidium. My path had straightened out again, until it was nearing the time for me to graduate and find a job.
Identification of a fish host of the inflated heelsplitter Potamilus inflatus (Bivalvia: Unionidae) with a description of its glochidium. Amer.
The minute shell structure of the glochidium of some species of the genera Unio, Potomida and Anodonta (Bivalvia, Unionacea).
Depending on the mussel species, a glochidium remains within a cyst for days to months (Arey, 1921, 1932; Waller and Mitchell, 1989; Walters and O'Dee, 1999; Rogers-Lowery and Dimock, 2006), during which time it may metamorphose into a juvenile.
The authors confirmed the accuracy of their glochidium key using tissue extracts from adults that were morphologically identified.
The odds against any one individual glochidium surviving are extremely large--thousands or millions of glochidia may be produced, but the vast majority never encounter a fish.
The unionid's life cycle has the larval stage, the glochidium, parasitic on a fish host.