fi·​ber | \ ˈfī-bər \

Definition of fiber

1 : a thread or a structure or object resembling a thread: such as
a(1) : a slender root (as of a grass)
(2) : an elongated tapering thick-walled plant cell void at maturity that imparts elasticity, flexibility, and tensile strength
b(1) : a strand of nerve tissue : axon, dendrite
(2) : one of the filaments composing most of the intercellular matrix of connective tissue
(3) : one of the elongated contractile cells of muscle tissue
c : a slender and greatly elongated natural or synthetic filament (as of wool, cotton, asbestos, gold, glass, or rayon) typically capable of being spun into yarn
d : mostly indigestible material in food (such as legumes, whole grains, and vegetables) that stimulates the intestine to peristalsis and promotes elimination of waste from the large intestine : bulk, roughage dietary fiber trying to get more fiber in her diet
2 : material made of fibers especially : vulcanized fiber
3a : an element that gives texture or substance
b : basic toughness : strength, fortitude
c : essential structure or character the very fiber of a person's being

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Other Words from fiber

fibered \ ˈfī-​bərd \ adjective

Examples of fiber in a Sentence

It's important to get enough fiber in your diet. What foods do you recommend as good sources of fiber? foods that are high in fiber The fabric is made from a mix of synthetic fibers. The natural fibers allow the fabric to breathe. The paper is made from both cotton and wood fiber. Nylon is a very strong man-made fiber. The police examined hair and bits of fiber found in the victim's car.
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Recent Examples on the Web

He is sent to Liaoyang near the North Korean border to help build a synthetic fiber factory. Josh Chin, WSJ, "Huawei CEO Says Company Doesn’t Spy for China, Praises Trump," 15 Jan. 2019 And because termites bring the toxic wood fibers back to the nest, bait stations are effective at wiping out the entire colonies. Joseph Truini, Popular Mechanics, "How to Get Rid of Termites," 8 Jan. 2019 Compared to textured cotton towels, the fibers are much smaller and finer, actively wicking water away without causing friction. Sarah Wu, Glamour, "This $30 Aquis Towel Completely Saved My Hair Color," 10 Dec. 2018 Bamboo is a soft, breathable fiber made from renewable bamboo grass. Hannah Morrill, ELLE Decor, "The Best Luxury Sheets For the Perfect Night's Sleep," 15 Nov. 2018 Reflectix: Any van life veteran knows about Reflectix ($52.89), a reflective insulation that’s fiber free, lightweight, and easy to install. Megan Barber, Curbed, "The ultimate van life shopping guide," 14 Nov. 2018 The second component is being able to use healing, cooling, and pressure to create something analogous to muscle fibers. Angela Chen, The Verge, "These are the technology advances that could end animal farming," 9 Nov. 2018 So instead, start your day off with a protein and fiber-rich breakfast. Jenna Rosenstein, Harper's BAZAAR, "The Holidays Are Coming—Here's How To Get Back On Track After a Big Meal," 19 Oct. 2018 Go easy on the spot treatments Yes, every fiber of your being wants to bomb your face with all the anti-acne creams and every beauty hack you’ve ever read — or at least reapply a spot treatment a zillion times throughout the day. Beth Janes, Seventeen, "What to Do the *Second* a Pimple Appears," 7 Aug. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fiber.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of fiber

1607, in the meaning defined at sense 1

History and Etymology for fiber

Middle French fibre, from Latin fibra

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Dictionary Entries near fiber

fiat money





fiber box

fiber can

Statistics for fiber

Last Updated

21 Jan 2019

Look-up Popularity

Time Traveler for fiber

The first known use of fiber was in 1607

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More Definitions for fiber



English Language Learners Definition of fiber

: plant material that cannot be digested but that helps you to digest other food

: a thin thread of natural or artificial material that can be used to make cloth, paper, etc.

: material (such as cloth) that is made from thin threads : something made of fibers


fi·​ber | \ ˈfī-bər \

Kids Definition of fiber

1 : a thread or a structure or object resembling a thread
2 : plant material that cannot be digested


variants: or chiefly British fibre \ ˈfī-​bər \

Medical Definition of fiber

1 : a thread or a threadlike structure or object: as
a : a strand of nerve tissue : axon, dendrite
b : one of the filaments composing most of the intercellular matrix of connective tissue
c : one of the elongated contractile cells of muscle tissue
2 : mostly indigestible material in food that stimulates the intestine to peristalsis

called also bulk, dietary fiber, roughage

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More from Merriam-Webster on fiber

Rhyming Dictionary: Words that rhyme with fiber

Thesaurus: All synonyms and antonyms for fiber

Spanish Central: Translation of fiber

Nglish: Translation of fiber for Spanish Speakers

Britannica English: Translation of fiber for Arabic Speakers Encyclopedia article about fiber

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a complex dispute or argument

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