fiber

noun

fi·​ber ˈfī-bər How to pronounce fiber (audio)
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
3
a
: 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
fibered 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.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
On May 8, Duffy announced a plan to completely rebuild the United States’ air traffic control system, replacing outdated telecommunications with new fiber, wireless and satellite technologies and equipping controllers with new radar, radios and voice switches. Suzanne Rowan Kelleher, Forbes.com, 21 May 2025 Polymers’ properties and chemical structures change as they are melted and reformed multiple times, and this method—which can be used on pellets, fibers, fabrics and garments—analyzes these changes. Sarah Jones, Sourcing Journal, 21 May 2025 These foods, such as leafy green vegetables, nuts, and seeds, provide essential vitamins, minerals, and dietary fiber that support overall health and well-being.5 Focus on consuming a variety of high- and low-oxalate foods. Roxana Ehsani, Health, 21 May 2025 This matters because wheat germ and bran contain important nutrients like protein, fiber, minerals and key vitamins. Daryl Austin, USA Today, 21 May 2025 See All Example Sentences for fiber

Word History

Etymology

Middle French fibre, from Latin fibra

First Known Use

1607, in the meaning defined at sense 1

Time Traveler
The first known use of fiber was in 1607

Browse Nearby Words

Cite this Entry

“Fiber.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fiber. Accessed 24 May. 2025.

Kids Definition

fiber

noun
fi·​ber ˈfī-bər How to pronounce fiber (audio)
1
: a thread or a structure or object resembling a thread: as
a
: a slender root (as of a grass)
b
: a long tapering thick-walled plant cell especially of vascular tissue
c
: a muscle cell
d
e
: a slender and very long natural or synthetic unit of material (as wool, cotton, asbestos, gold, glass, or rayon) usually able to be spun into yarn
f
: mostly indigestible material in food that stimulates the intestine to move its contents along

called also bulk, roughage

2
: material made of fibers
3
: basic toughness : strength
moral fiber

Medical Definition

fiber

noun
fi·​ber
variants or chiefly British fibre
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

More from Merriam-Webster on fiber

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