break down

4 meanings

Meanings
  1. 1 stop working (a car, machine, or system) B1
  2. 2 separate something into smaller parts or groups B2
  3. 3 start crying or lose control of your emotions B2
  4. 4 separate into smaller parts through a chemical process B2
1 break down

stop working (a car, machine, or system)

B1

What does "break down" mean in this sense?

Something that breaks down stops working completely and usually needs to be fixed or repaired. This phrasal verb is used for physical things like cars, machines, or appliances, but also for more abstract things like relationships, marriages, and negotiations. The important thing to notice is that the thing that fails is always the subject — the car breaks down, the talks break down, the system breaks down. It suggests a more complete failure, not just a small problem or a brief pause. You will hear it in everyday conversation ('My laptop broke down') and also in news articles about failed diplomatic talks or collapsed relationships.

Examples

How to use it

subject (machine/vehicle) + break down

The most common use — a vehicle or device fails and stops working, with the failing thing as the subject.

The bus broke down on the way to the airport, so we had to get a taxi.

subject (relationship/process) + break down

Used for abstract things like marriages, negotiations, or systems that fail or collapse.

The trade talks broke down after the two sides couldn't agree on key issues.

break down + location/time phrase

A location or time phrase is often added to give context to where or when the failure happened.

Our heating broke down in the middle of January, which was very inconvenient.

subject + have/has broken down

The present perfect is often used to talk about a recent failure that is still relevant now.

The lift has broken down again, so we'll have to use the stairs.

subject + break down + because of / due to + cause

To explain the cause of the failure, use 'because of' or a similar phrase — not a direct object after 'break down'.

The machine broke down because of a fault in the electrical system.

Common Collocations

car breaks downmachine breaks downmarriage breaks downnegotiations break downsystem breaks downtalks break down

Common Mistakes

Using it transitively

In this sense, 'break down' is intransitive — the failing thing is the subject, not an object. You cannot use another noun directly after 'break down' to show what caused the failure.

✗ The cold weather broke down my car.
✓ My car broke down because of the cold weather.
Confusing with 'break up'

'Break up' is used when two people end a romantic relationship. 'Break down' is used for marriages (more formal), negotiations, systems, or machines — not for dating relationships.

✗ After three years together, their relationship broke down and they stopped dating.
✓ After three years together, they broke up. / Their marriage broke down after years of difficulties.
Confusing with 'cut out'

'Cut out' describes a sudden, brief stop — like an engine stalling for a moment. 'Break down' means a more complete failure that requires repair or intervention.

✗ The engine cut out completely and needed a full repair.
✓ The engine broke down completely and needed a full repair.

Usage

This phrasal verb is neutral and works in both everyday speech (cars, appliances) and formal writing (negotiations, relationships, systems). When the subject is an abstract noun like 'talks' or 'trust', it is especially common in news and academic writing.

2 break sth down

separate something into smaller parts or groups

B2

Sense 2: What does "break sth down" mean?

To break down something means to take a complex whole and divide it into smaller, more manageable parts or categories so that it is easier to understand or analyse. This is especially useful when dealing with complicated information, such as financial data, a multi-step process, or a difficult concept. The idea is not random splitting but a deliberate, logical separation — you end up with clear components or categories that reveal structure. You will hear this phrasal verb constantly in business meetings, academic writing, and educational settings. What makes it distinctive is that it combines the idea of reducing complexity with the goal of making things clearer.

Examples

How to use it

break down + noun object

The most common pattern: a person breaks down a piece of data, a cost, a problem, or a process into its parts.

The consultant broke down the budget so the team could see where money was being spent.

break + pronoun + down

When a pronoun replaces the object, it must go between 'break' and 'down' — it cannot come after 'down'.

The figures looked confusing at first, but she broke them down clearly in her presentation.

break down + noun + into + categories/parts

Adding 'into' followed by a noun phrase specifies what the resulting components or categories are.

The trainer broke the course down into four modules, each covering a different skill.

be broken down + by + basis of division

The passive form with 'by' is common in formal or written contexts when the agent is less important than the result, and it specifies how the division was made.

The survey results were broken down by age group and geographical region.

break down + noun + into + steps/stages

Particularly common in instructional or explanatory contexts where a process is divided into a sequence of actions.

Let me break the application process down into three simple steps.

Common Collocations

break down the databreak down the costsbreak down the processbreak down the problembreak down into stepsbreak down by category

Common Mistakes

Pronoun after the particle

When the object is a pronoun, it must go between 'break' and 'down', not after 'down'. Placing a pronoun after the particle is ungrammatical in English.

✗ Can you break down it into smaller sections?
✓ Can you break it down into smaller sections?
Confusing with the mechanical or emotional sense

This sense of 'break down' always requires a direct object — you are breaking something down. If there is no object, readers may interpret the sentence as describing a machine stopping or someone becoming emotional, both of which are intransitive.

✗ The team broke down during the analysis.
✓ The team broke down the data during the analysis.
Using 'break up' instead of 'break down'

'Break up' suggests physical splitting or dispersal, while 'break down' is used for analytical or logical division into categories and components. In professional or academic contexts, 'break down' is the correct choice.

✗ We need to break up the costs by department before the meeting.
✓ We need to break down the costs by department before the meeting.

Usage

This sense of 'break down' is neutral and works in both formal writing and everyday speech. It is especially common in business and academic contexts when analysing or explaining complex information.

3 break down

start crying or lose control of your emotions

B2

Sense 3: What does "break down" mean?

To break down in this sense means to suddenly lose control of your emotions, usually to the point of crying. It describes an involuntary reaction — something that happens to you rather than a choice you make. The feeling becomes too strong to hold back, and you give in to it. This phrasal verb is often used in emotionally charged situations such as receiving bad news, attending a funeral, or speaking publicly about something painful. Importantly, it implies a visible, outward loss of control, not just feeling sad on the inside.

Examples

How to use it

subject + break down

The most common pattern — the verb is intransitive, so it stands alone without any object.

She broke down as soon as she read the message.

break down + in tears / sobbing / crying

A very common fixed-feeling collocation that specifies how the emotional response is expressed.

He broke down in tears halfway through his speech.

break down + at / during / when / while + trigger

A prepositional phrase or clause is often added to show what caused the emotional reaction.

She broke down during the interview when they asked about her late husband.

completely / totally / nearly + break down

Adverbs like 'completely' or 'nearly' are often used to intensify or qualify the degree of emotional loss of control.

He nearly broke down while delivering the eulogy, but managed to keep his composure.

break down + in front of / on the phone

A phrase can be added to show the location or social context in which the breakdown happens.

I broke down on the phone when my sister told me what had happened.

Common Collocations

break down in tearsbreak down cryingbreak down at the funeralbreak down completelybreak down during the speechbreak down at the news

Common Mistakes

Trying to use it with an object

In this emotional sense, 'break down' is always intransitive — it cannot take an object. Learners sometimes add one by mistake, possibly by confusing it with the transitive analytical sense.

✗ The news broke down her completely.
✓ She completely broke down when she heard the news.
Confusing the emotional sense with the machine sense

When a person is the subject, 'break down' means to lose emotional control. When a machine or vehicle is the subject, it means to stop working. Check whether your subject is a person or a thing.

✗ My laptop broke down when I heard the news. (if you mean to express an emotional reaction)
✓ I broke down when I heard the news.
Using the future continuous for planned emotional reactions

Because breaking down is an involuntary reaction rather than a deliberate act, it sounds unnatural to say someone 'will be breaking down' as if it were a planned event. Use other tenses for predictions or hypotheticals.

✗ She will be breaking down at the ceremony tomorrow.
✓ She might break down at the ceremony tomorrow.

Usage

This phrasal verb is neutral in register and can be used in both formal writing and everyday speech. It specifically implies an involuntary, visible loss of emotional control — usually crying — rather than simply feeling upset.

4 break sth down

separate into smaller parts through a chemical process

B2

Sense 4: What does "break sth down" mean?

This sense of 'break down' describes a chemical or biological process in which a substance is transformed into different, typically simpler substances. It is not just about splitting something into pieces — the key idea is that the original substance changes into something chemically distinct. For example, when your body digests food, enzymes break down proteins into amino acids, which are chemically different from the original protein. You will most often encounter this meaning in biology, chemistry, environmental science, and medical texts. Common agents in these sentences are enzymes, bacteria, acids, and other natural processes, acting on substances like fats, carbohydrates, toxins, or organic matter.

Examples

How to use it

agent + break down + substance + into + resulting substance

This is the most complete and common pattern, specifying both the substance being decomposed and what it becomes.

Stomach acid breaks down fats into fatty acids and glycerol.

substance + break down + into + resulting substance

Used when the focus is on the substance itself rather than the agent causing the decomposition.

Glucose breaks down into carbon dioxide and water during cellular respiration.

substance + be broken down + into + resulting substance

The passive is very common in scientific and academic writing when the agent is unknown, unimportant, or already understood.

Cellulose is broken down into simple sugars by specialised bacteria in the gut.

agent + break + pronoun + down

When the substance is replaced by a pronoun, it must go between 'break' and 'down', never after 'down'.

The liver processes alcohol and breaks it down into less harmful substances.

substance + break down + (without 'into' phrase)

The 'into + resulting substance' phrase can be left out when the focus is simply on whether or not decomposition occurs.

Some synthetic materials do not break down easily in the environment.

Common Collocations

break down foodbreak down proteinsbreak down wastebreak down compoundsbreak down pollutantsbreak down molecules

Common Mistakes

Omitting 'into' when the product is mentioned

When you want to name the resulting substance, you need 'into' between 'break down' and the product. Leaving it out makes the sentence sound incomplete or unnatural.

✗ Enzymes break down proteins amino acids.
✓ Enzymes break down proteins into amino acids.
Wrong pronoun placement

When the object is a pronoun like 'it' or 'them', it must come between 'break' and 'down'. Placing it after 'down' is ungrammatical.

✗ Bacteria break down them in the soil.
✓ Bacteria break them down in the soil.
Confusing 'break down' with 'break up'

'Break up' suggests splitting something into similar pieces of the same material, whereas 'break down' implies a chemical transformation into different substances. They are not interchangeable in scientific contexts.

✗ Enzymes break up proteins into amino acids.
✓ Enzymes break down proteins into amino acids.

Usage

This sense of 'break down' is mainly used in scientific and educational writing rather than everyday conversation. It is common in biology, chemistry, and environmental science contexts at B2 level and above.

Frequently Asked Questions

Can 'break down' be used in the passive, like 'The car was broken down'?

No — in this sense, 'break down' cannot be made passive. Because there is no object (the car breaks down by itself), there is nothing to move into the subject position of a passive sentence. Always keep the failing thing as the subject: 'The car broke down', not 'The car was broken down'.

Does 'break down' always refer to machines and vehicles?

No, it's also very common with abstract subjects like relationships, marriages, negotiations, and systems. In news and formal writing, you'll often see sentences like 'The peace talks broke down' or 'Trust between the two parties broke down'. The subject always tells you what type of failure is meant.

Can a person be the subject of 'break down'?

Not in this sense. If the subject is a person, 'break down' means to lose emotional control and cry — for example, 'She broke down in tears'. If you want to talk about a machine, system, or process failing, the subject must be that thing, not a person.

Is 'break down' only used in informal conversation?

No, it works in both informal and formal contexts. In everyday speech, it's common for cars and appliances. In journalism and formal writing, it's regularly used for negotiations, systems, and relationships — making it a useful phrasal verb to know at all levels.

What kinds of things can 'break down' in this sense?

A wide range of subjects are natural: vehicles (a car, a bus), machines and devices (a boiler, a computer, a lift), and abstract processes or relationships (negotiations, a marriage, a supply chain, a system, trust). The common idea is that something stops functioning properly and needs some kind of fix or resolution.

What kinds of things can you 'break down'?

You can break down almost anything that has structure or complexity — data, costs, a process, an argument, a problem, a schedule, or a report. The key idea is that the thing you break down can be divided into meaningful parts or categories. Abstract or intellectual things are just as natural as concrete ones in this sense.

Does 'break down' always mean the same thing?

No — 'break down' has several different meanings depending on context. This sense (dividing something into parts for analysis) always has a direct object. Two other common senses — a machine stopping working, or someone collapsing emotionally — are both intransitive and have no direct object. Context usually makes the meaning clear.

Can I use 'break down' in passive sentences?

Yes, the passive works very naturally here, especially in business reports, academic writing, and data analysis. Forms like 'the results were broken down by region' or 'costs can be broken down into three categories' are common and correct.

Can I say 'I am breaking down the data' (present continuous)?

It is not wrong, but it sounds slightly unnatural unless you are specifically describing an ongoing analysis happening right now. In most situations, the simple present ('I usually break down the data first'), past simple, or imperative feel more natural with this phrasal verb.

What is the difference between 'break down into' and 'break down by'?

'Break down into' is used to name the resulting categories or components — for example, 'break the project down into phases'. 'Break down by' indicates the criterion or basis used for dividing — for example, 'the results were broken down by age'. Both patterns are common and often appear together in the same sentence.

Does 'break down' always involve crying, or can it mean other kinds of emotional reaction?

In this sense, 'break down' is most strongly associated with crying or weeping. It always implies a visible loss of emotional control triggered by grief, distress, or overwhelming stress. If the reaction is laughter, a different phrasal verb — 'break up' — is more typically used.

Can I say 'break down' to describe a gradual process, or is it always sudden?

It usually describes something fairly sudden — the moment when someone can no longer hold their emotions back. You wouldn't typically use it for a slow, gradual process of becoming upset. The sense of a threshold being crossed is central to its meaning.

Does 'break down' have other meanings? How will I know which one is being used?

Yes, 'break down' has several meanings. The subject is the main clue: if the subject is a person and the context involves emotion, it means losing emotional control. If the subject is a machine or vehicle, it means stopping working. Other contexts involve abstract subjects like negotiations or data.

Is 'break down in tears' a set phrase, or can I use other words after 'in'?

'Break down in tears' is by far the most common collocation, and it has an almost fixed quality to it. You can also say 'break down sobbing' or 'break down crying', but these use a different structure (verb + -ing). 'Break down in laughter' is not standard for this sense.

Does 'break down' always need an agent, like bacteria or an enzyme?

No — the agent is optional. You can say 'Proteins are broken down into amino acids' without mentioning what causes the process. However, if you do want to mention the agent, it typically comes before the verb: 'Enzymes break down proteins into amino acids.'

Can I use 'break down' in the present continuous, like 'is breaking down'?

It sounds unnatural in scientific or academic writing, where the simple present or passive is strongly preferred. In a more informal or narrative context it is possible, but for essays, reports, or textbooks, stick to forms like 'breaks down', 'is broken down', or 'has been broken down'.

Is 'break down' the same as 'decompose'?

'Break down' and 'decompose' overlap significantly in meaning, and in many sentences you can use either. However, 'break down' is more common in educational materials, biology textbooks, and everyday scientific explanation, while 'decompose' tends to appear more in formal chemistry and biological decay contexts. For B2-level writing and exams, 'break down' is a safe and natural choice.

Does this meaning of 'break down' only apply to living or biological processes?

Not exclusively — it covers any chemical transformation, whether biological or not. Bacteria and enzymes are common agents, but acids, natural weathering, and industrial chemical processes can also 'break down' substances. What matters is that the substance is transformed into something chemically different, not just physically separated.

Can I use this sense of 'break down' to talk about things like plastic or pollution?

Yes, this is a very natural use. Sentences like 'Plastic does not break down quickly in landfill' or 'Certain fungi can break down industrial pollutants' are common in environmental science writing. The key is that the substance is undergoing chemical change, not just being moved or collected.

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