Meaning & use
fiber
Last updated
Meanings
noununcountable
The indigestible part of plant foods that helps food move through your body.
Grammar: Used as a mass noun: eat more fiber, not eat more fibers.
Patterns
- dietary fiber
- a good source of fiber
- high in fiber
Doctors recommend eating more fiber to keep your digestion healthy.
Beans and whole grains are excellent sources of dietary fiber.
This cereal is high in fiber and low in sugar.
nouncountable
A thin thread or strand of material, either natural or made by people.
Grammar: Countable when talking about individual strands: a fiber, several fibers.
Patterns
- natural fibers
- synthetic fibers
- a fiber of something
Cotton fibers are spun into thread to make cloth.
The rope is made from strong synthetic fibers.
Under the microscope, you can see the individual fibers in the paper.
nouncountable or uncountable
A material made from long thin threads, used for making cloth or rope.
Grammar: Can be countable (a fiber) or uncountable (fiber as a material).
Patterns
- glass fiber
- carbon fiber
- optical fiber
The boat is made of lightweight carbon fiber.
Glass fiber is used to make insulation and car parts.
Optical fiber carries telephone and internet signals.
noununcountableformal
A quality in a person's character that gives them strength and determination.
Grammar: Used in the phrase 'moral fiber' to talk about someone's inner strength.
Patterns
- moral fiber
- show fiber
The crisis tested the moral fiber of the whole community.
She showed real fiber by refusing to give up.
Word forms
| plural | fibers |
|---|
Common combinations
- dietary fiber
- Nutritionists say we should get more dietary fiber from fruits and vegetables.
- high in fiber
- Oats are high in fiber and can help lower cholesterol.
- natural fiber
- Wool is a natural fiber that keeps you warm.
- optical fiber
- Optical fiber allows data to travel at very high speeds.
- a source of fiber
- Whole-grain bread is a good source of fiber.
Synonyms and how they differ
- roughage
- An older, less common word for dietary fiber; it is used mainly in health contexts and sounds a bit old-fashioned.
- strand
- A single thin piece of something like hair or thread; it is more specific than fiber and does not refer to food.
- filament
- A very thin thread, often used for man-made materials or in technical contexts; more formal than fiber.
Word family
- fibrous adjective
- Containing or looking like fibers, as in fibrous tissue or fibrous vegetables.
- fiberglass noun
- A strong lightweight material made from glass fibers.
- fiber-optic adjective
- Relating to technology that uses thin glass fibers to carry light signals.
Commonly confused: fiber or fibre?
fiber vs fibre
The British spelling of the same word. Use 'fiber' in American English and 'fibre' in British English.
Practice
Which sentence uses 'fiber' correctly?
Choose one answer.
In the dietary sense, 'fiber' is uncountable, so you say 'important fiber' or 'a lot of fiber,' not 'fibers.' Option 3 is correct because it treats fiber as a mass noun. Options 1, 2, and 4 wrongly use 'fiber' as a countable noun in this sense.
Make it your own
Write a sentence using “fiber”, then check it and compare it with the examples above.