Fibre vs Fiber | Spelling & Explanation

Fiber is the American English spelling of the noun that refers to the threads that make up a fabric. In British English, it is spelled fibre. The meaning in both variants of the language is the same, even when applied to thoroughly modern uses like “fiberoptic/fibreoptic cable.”

Fibre or fiber in a sentence examples
The problem with clothes made from synthetic fibre/fiber is that they are often sweaty and uncomfortable to wear.

Gone are the days of connecting to the internet via your phone line; optical fibre/fiber is the most popular choice now.

Carbon fibre/fiber is so strong and light that it can be found in everything from spacecraft to road bikes.

Fibre or fiber

Fibre/fiber can refer to spun threads of cotton, wool, or synthetic material that are used to make fabric for clothes or upholstery. It can also be a synonym for “roughage” in relation to dietary fibre/fiber, and it can be used to describe the makeup of muscles (e.g., “Slow-twitch muscle fibre/fiber is essential for good sprinting performance”).

You will also find fibre/fiber used figuratively to refer to a person’s character (e.g., “He felt her pain in every fibre/fiber of his being”).

Regardless of meaning, fibre is used in British English and fiber in American English.

Fibre or Fiber in a sentence examples
Many doctors and nutritionists recommend a diet high in fibre/fiber to aid weight loss and promote heart health.

The fibre/fiber in a rope is twisted together in order to increase its tensile strength.

The silk fibre/fiber of the silk moth’s cocoon is between 980 and 3,000 feet (300 to 900 m) long.

Fibres vs fibers

The plural form of fibre/fiber follows the same spelling as the singular: in American English it is spelled fibers, and in British English fibres is the correct spelling.

Fibres vs fibres in a sentence examples
Many old towns in England have a “Rope Walk,” which is a long, straight passageway where the individual fibres/fibers were twisted together to make rope.

Fibreglass/fiberglass is a strong and versatile composite material of glass fibres/fibers held together by strong polyester resin or similar.

Muscle stiffness after exercise is caused by tiny tears in the muscle fibres/fibers.

Main differences between American and British English

American and British English are very similar, but there are a few main differences in spelling. Five important differences are:

Difference Rule Examples
-or vs -our In American English, many Latin-derived words end in -or. Behavior or behaviour

Labor or labour

Favor or favour

Favorite or favourite

Color or colour

Honor or honour

In British English, these same words end in -our.
-er vs -re In American English, some French, Latin, or Greek words end in -er. Theater or theatre

Center or centre

Meter or metre

Liter or litre

Saber or sabre

Fiber or fibre

In British English, these same words end in -re.
-ize vs -ise In American English, many Greek-derived words end in -yze or -ize. Realize or realise

Recognize or recognise

Analyze or analyse

Organize or organise

Minimize or minimise

Finalize or finalise

In British English, these words end in -yse or -ise.
-ed vs -t In American English, most verbs are regular and form their past tense with the suffix -ed. Learned or learnt

Burned or burnt

Kneeled or knelt

Dreamed or dreamt

Smelled or smelt

Spelled or spelt

In British English, some of these verbs are irregular and form their past tense with the suffix -t.
Single vs double consonant In American English, many words are spelled with a single consonant. Modeling or modelling

Traveling or travelling

Canceled or cancelled

Labeled or labelled

Buses or busses

Focused or focussed

In British English, these same words are often spelled with a double consonant.

Frequently asked questions about fibre or fiber

What does fiberous mean?

Fiberous is a misspelling of the adjective fibrous, meaning “made up of fibre or fiber.” The misspelling probably arises because of the way the root word is spelled in American English (e.g., “fiber”).

The QuillBot Grammar Checker has selectable language regions to ensure you always have the right spelling of fibrous.

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Trevor Marshall, MSc

Trevor has a BA in English Literature & Language and an MSc in Applied Social Studies. He has been a teacher for 25 years, with 15 years experience teaching ESL alongside 1st language students.