fibers

IPA/fˈaɪbəz/
KK[fˈaɪbɚz]IPA/fˈaɪbərz/

fibers — noun

1. the long, thin threads that make up plants or human-made materials, often spun t

1.nounB1
Definition

the long, thin threads that make up plants or human-made materials, often spun together to make cloth, rope, or other woven goods.

Example

Trang spins cotton fibers into thread on her grandmother's old wooden wheel.

plural countable: spins [material] fibers into [product]

The factory in Da Nang weaves bamboo fibers into soft summer shirts.

collocation: weave [plant] fibers into [garment]

Common collocations
  • natural fibers
  • synthetic fibers
  • cotton fibers
  • wool fibers
  • spin fibers
  • weave fibers
Synonyms
  • filaments

    more technical; suggests very thin, often artificial threads

  • strands

    any single thread-like piece; less material-focused than fibers

  • threads

    everyday word; usually already spun or processed, while fibers are often raw

Grammar Patterns

fibers of [material]

made from [adjective] fibers

Usage Note

Frequently plural. Subject or object is typically a material noun (cotton, wool, glass, plastic); commonly appears with verbs like spin, weave, twist, blend.

Common Mistakes

My shirt is made of one fiber.
My shirt is made of cotton fibers.
when describing what cloth is made from, use the plural; singular sounds unnatural here.
I bought some fiber for my dress.
I bought some fabric for my dress.
fibers are the raw threads; fabric is the finished cloth.

2. the thin, thread-like parts inside the body that form muscles, nerves, and other

2.nounB2
Definition

the thin, thread-like parts inside the body that form muscles, nerves, and other tissues, allowing them to stretch, contract, or send signals.

Example

Heavy lifting can tear small muscle fibers, which heal back stronger after rest.

collocation: tear muscle fibers

The doctor showed Eli a photo of damaged nerve fibers in his lower back.

collocation: nerve fibers

Common collocations
  • muscle fibers
  • nerve fibers
  • tear fibers
  • contract
  • damaged fibers
Synonyms
  • filaments

    common in scientific writing for the very thin structures inside cells

  • tissue

    broader term; tissue is made of many fibers plus other cells

Grammar Patterns

muscle / nerve fibers

fibers of the [body part]

Usage Note

Almost always plural and typically preceded by the body part it belongs to (muscle, nerve, heart, optic). Distinguish from sense 1 by the body context.

Common Mistakes

I pulled a muscle fiber in the gym.
I pulled some muscle fibers in the gym.
injuries normally affect many fibers at once; plural sounds more natural.

3. the rough parts of plant-based foods like fruits, vegetables, and whole grains t

3.nounB1
Definition

the rough parts of plant-based foods like fruits, vegetables, and whole grains that the body cannot break down, helping the stomach and bowels work smoothly.

Example

Oats, beans, and apples give João most of his daily fibers.

collocation: [foods] give [person] fibers

Doctors told Kian to eat more whole grains because his diet was low in fibers.

collocation: low in fibers

Common collocations
  • dietary fibers
  • high in fibers
  • soluble fibers
  • natural fibers
Synonyms
  • roughage

    older everyday word for the same dietary substance

  • bulk

    informal; emphasizes the volume that fiber adds to food

Grammar Patterns

dietary fibers

[food] is high in fibers

Usage Note

In nutrition contexts the singular 'fiber' is more standard than 'fibers'; the plural appears mainly when listing types (soluble fibers, dietary fibers) or in informal speech.

Common Mistakes

This bread has many fibers.
This bread is high in fiber.
for the dietary substance, the singular uncountable form is more natural in everyday English.

4. a person's basic strength of character — the inner quality that allows someone t

4.nounC1
Definition

a person's basic strength of character — the inner quality that allows someone to act with courage, honesty, or principle, especially under pressure.

Example

Soraya showed real moral fiber when she reported the unsafe building to the inspector.

fixed phrase: moral fiber

The old captain said modern leaders lacked the moral fiber of his generation.

collocation: lack the moral fiber

Common collocations
  • moral fiber
  • lack moral fiber
  • test someone's fiber
Synonyms
  • backbone

    everyday word; emphasizes courage to stand firm

  • character

    broader; covers all stable personal qualities, not only strength

  • mettle

    literary; the spirit to face difficulty bravely

Antonyms
  • weakness

    general lack of resolve or strength

Grammar Patterns

moral fiber

[person] lacks the fiber to [verb]

Usage Note

Almost always singular ('fiber') even on the 'fibers' page; the plural is non-standard for this sense. Most commonly appears in the fixed phrase 'moral fiber' or after 'lack/have/test the X fiber to do something'.

Common Mistakes

She has strong moral fibers.
She has strong moral fiber.
in this abstract sense, English uses the singular uncountable form.

Word family

Synonym discussion

Sense: noun/1

All four describe long, thin, thread-like pieces, but their typical use differs. 'Fibers' is the most general scientific term for the raw thread-like material that makes up plants, animal tissues, or man-made cloth (cotton fibers, glass fibers). 'Filaments' suggests something very fine and often artificial — a light bulb filament, the filaments inside fiber-optic cables — and is more technical. 'Threads' are usually already processed: spun, twisted, and ready to be sewn or woven. A tailor buys threads; a textile scientist studies fibers. 'Strands' is the most everyday and least material-bound — you can have strands of hair, strands of a story, or strands of DNA. Compare: 'cotton fibers' (raw plant material) → 'cotton threads' (spun and ready to sew) → 'a strand of cotton' (just one piece, no material focus).

fibers ↗filaments ↗threads ↗strands ↗

Common collocations

Nouns

  • cotton fibers
  • glass fibers
  • muscle fibers
  • nerve fibers
  • dietary fibers
  • moral fiber

Phrases

  • natural fibers
  • synthetic fibers
  • high in fibers
  • rich in fibers

Prepositions

  • of (fibers of cotton)
  • in (in fibers)

Etymology

LatinOld FrenchMiddle EnglishEnglish

Comes through Old French 'fibre' from Latin 'fibra', meaning a thread or filament — originally used by Roman writers for the thin strings inside plants and animal bodies. English borrowed the word in the late 1300s for the small threads inside leaves and muscle. American English standardized the spelling 'fiber' in the early 1800s under Noah Webster, while British English kept 'fibre'; the figurative sense of 'moral fiber' (inner strength) emerged in the 1800s by metaphor from the strong, supporting threads inside a body.