buffer

buffer — noun

1. a person, thing, or arrangement that takes some of the danger, pressure, or trou

1.nounC1
Definition

a person, thing, or arrangement that takes some of the danger, pressure, or trouble before it reaches someone or something else.

Example

The thick hedge acts as a buffer against wind from the sea.

act as a buffer against + noun

Marta's assistant acted as a buffer, keeping rude callers away from her.

person as buffer from annoyance

Common collocations
  • buffer against inflation
  • financial buffer
  • act as a buffer
  • provide a buffer
  • protective buffer
Synonyms
  • cushion

    often used for something that softens financial or emotional shocks

  • safeguard

    more formal, especially for rules or systems that protect people

  • shield

    stronger image of direct protection from harm or attack

Grammar Patterns

a buffer against + noun

act as a buffer

Usage Note

Distinguish from noun sense 2: this sense can be a person, a service, or money kept ready, not only a physical strip or space. It often appears with 'against' plus the danger or problem.

Common Mistakes

My sister is a buffer of me and stress.
My sister is a buffer against stress for me.
use 'against' for the danger; 'of' is not used here.

2. a strip, layer, or empty space left around something, or placed between two thin

2.nounC1
Definition

a strip, layer, or empty space left around something, or placed between two things, so they do not touch or affect each other directly.

Example

Workers left a grass buffer between the river and the new road.

buffer between + two places

Each young tree needs a ring of mulch as a buffer around its trunk.

buffer around + noun

Common collocations
  • buffer zone
  • buffer strip
  • buffer area
  • green buffer
  • create a buffer
Synonyms
  • barrier

    stronger and more direct; it blocks contact rather than just reducing it

  • zone

    common when the protected area is wide or officially marked

  • margin

    used for an extra space around the edge of something

Grammar Patterns

a buffer between + two things

a buffer around + noun

Usage Note

Subject is usually a strip of land, a fence, plants, or open space. Distinguish from noun sense 1, where the buffer may be a person or a financial arrangement rather than a physical gap.

Common Mistakes

They planted trees as a buffer from the road and the houses.
They planted trees as a buffer between the road and the houses.
when two sides are separated, use 'between'.

3. a part of computer memory where data waits briefly before the machine uses it or

3.nounB2
Definition

a part of computer memory where data waits briefly before the machine uses it or sends it on.

Example

The video paused because the buffer was empty for a moment.

the buffer was empty

Large photos sat in the buffer before the printer started.

sit in the buffer

Common collocations
  • memory buffer
  • print buffer
  • buffer size
  • fill the buffer
  • clear the buffer
Synonyms
  • cache

    another kind of temporary storage, usually for faster access rather than data flow timing

  • queue

    focuses on the ordered line of data rather than the memory area itself

  • temporary memory

    plain explanatory phrase rather than a technical term

Grammar Patterns

data in the buffer

clear/fill the buffer

Usage Note

Computing only. Unlike noun sense 5, this is not extra physical supply; it is temporary memory used to smooth the flow of data between devices or stages.

Common Mistakes

The file stayed in buffer.
The file stayed in the buffer.
this sense normally takes 'the' when naming the memory area.

4. a supply of goods or raw materials kept ready so work can continue if fresh supp

4.nounC1
Definition

a supply of goods or raw materials kept ready so work can continue if fresh supplies are delayed or suddenly run short.

Example

The printer keeps a paper buffer so orders can still go out.

keep a paper buffer

A buffer stock of rice helped the store during last month's delivery strike.

buffer stock collocation

Common collocations
  • buffer stock
  • cash buffer
  • inventory buffer
  • larger buffer
  • keep a buffer
Synonyms
  • reserve

    general word for something kept ready for later use

  • stockpile

    usually larger and more deliberate, often for emergencies

  • safety stock

    technical business term for extra inventory kept to avoid shortages

Antonyms
  • shortage

    a situation where there is not enough supply

Grammar Patterns

keep a buffer of + materials

buffer stock

Usage Note

Common in business, factory, and supply-chain contexts. Often appears in the fixed phrase 'buffer stock', but it can also be a cash buffer or time buffer in planning.

Common Mistakes

The shop kept buffer materials for winter.
The shop kept a buffer of materials for winter.
the noun needs an article or the fixed phrase 'buffer stock'.

5. a heavy metal piece on a railway vehicle, or fixed at the track end, that absorb

5.noun
Definition

a heavy metal piece on a railway vehicle, or fixed at the track end, that absorbs force in a crash.

Example

Before dawn, the mechanic checked both buffers on the empty passenger car.

check both buffers on a rail car

At coupling time, the front buffers met before the wagons locked together.

front buffers meet during coupling

Common collocations
  • front buffer
  • rear buffer
  • track buffer
  • damaged buffer
Synonyms
  • bumper

    broader everyday word for the impact-reducing part on a vehicle; less rail-specific

  • stop block

    refers specifically to the structure at the end of the track, not the part on the train

Grammar Patterns

front/rear buffer

track buffer

Usage Note

Used mainly in British rail contexts. In everyday American English, people are more likely to say 'bumper' for road vehicles; this rail sense is specific to trains and tracks.

6. a substance added to a liquid to stop its level of acid or alkali from changing

6.noun
Definition

a substance added to a liquid to stop its level of acid or alkali from changing too easily.

Example

The teacher added a buffer so the blue liquid stayed at the same pH.

add a buffer to keep pH steady

Without a buffer, the test liquid soon became too acidic to use.

without a buffer

Common collocations
  • phosphate buffer
  • buffer solution
  • add a buffer
  • natural buffer
Synonyms
  • buffer solution

    more exact term when the substance is already prepared as a solution

  • stabilizer

    broader scientific word; not limited to acidity

Grammar Patterns

add a buffer to + liquid

buffer solution

Usage Note

Common in chemistry and biology. The object being protected is usually a liquid or body fluid, and the point is to keep the acidity level steady within limits.

7. an old man spoken of in a mocking or mildly rude way.

7.noun
Definition

an old man spoken of in a mocking or mildly rude way.

Example

Listen to that old buffer, still telling school stories after lunch.

old buffer as dismissive label

At the bus stop, Aunt Jo muttered that the old buffer never stopped grumbling.

Common collocations
  • old buffer
  • silly buffer
  • forgetful old buffer
Synonyms
  • codger

    also old-fashioned; can sound comic rather than rude

  • old fool

    plainer and more directly insulting

  • geezer

    in British English, often less insulting and sometimes friendly

Grammar Patterns

old/silly buffer

Usage Note

British and old-fashioned. Usually said with little respect, often together with adjectives like 'old', 'silly', or 'stupid', so learners should avoid using it about real people.

Idioms

When a plan or someone's career suddenly stops being successful.

Maya's business plan hit the buffers after the bank refused funding.

Did Diego's acting career hit the buffers after that bad review?

buffer — verb

Word family

  • buffered
    adjectiveC1

Synonym discussion

Sense: noun/1

These words all involve protection, but they highlight different kinds of help. A buffer takes the force of something before it reaches the target, so it often appears with money, space, or another person standing in the middle. A cushion is especially good for softening shocks, whether physical or financial, and sounds slightly more everyday. A shield suggests direct defence from danger, attack, or criticism. A safeguard is more formal and often names a rule, system, or legal measure put in place beforehand. So a hedge can be a buffer against wind, emergency savings can cushion a family during a hard month, a bodyguard shields a singer from fans, and safety checks act as safeguards before a machine is used.

Common collocations

Phrases

  • act as a buffer
  • serve as a buffer
  • create a buffer
  • buffer against

Prepositions

Etymology

Old FrenchEnglish

The word seems to go back to an older French form linked with the sound or force of a blow. In English, it first became common for the railway part that takes the shock when trains meet or stop. From that solid physical picture, the meaning widened to anything that absorbs pressure, keeps two sides apart, or softens sudden change. Later science used it for substances that keep liquids steady, and computing took it over for temporary storage that smooths the flow of data.