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[fahy-bruh l, fib-ruh l] /ˈfaɪ brəl, ˈfɪb rəl/
a small or fine fiber or filament.
Botany. any of the delicate hairs on the young roots of some plants.
Cell Biology. any threadlike structure or filament.
Origin of fibril
1655-65; < New Latin fibrilla, equivalent to Latin fibr(a) fiber + -illa diminutive suffix
Related forms
fibrillar, adjective
fibrillose, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for fibril


noun (pl) -brils, -brillae (-ˈbrɪliː)
a small fibre or part of a fibre
(biology) a threadlike structure, such as a root hair or a thread of muscle tissue
Derived Forms
fibrilar, fibrillar, fibrillose, adjective
fibrilliform, adjective
Word Origin
C17: from New Latin fibrilla a little fibre
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
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Word Origin and History for fibril

1680s, back-formation from Modern Latin fibrilla, diminutive of Latin fibra (see fiber).

Online Etymology Dictionary, © 2010 Douglas Harper
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fibril in Medicine

fibril fi·bril (fī'brəl, fĭb'rəl) or fi·bril·la (fī-brĭl'ə)
A minute fiber.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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fibril in Science
  (fī'brəl, fĭb'rəl)   
Any of various threadlike fibers or filaments that are constituent parts of a cell or larger structure. Cellulose fibrils are the main component of cell walls in plants. Fibrils make up the contractile part of striated muscle fiber in the body.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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