flatline: meaning, definition, pronunciation and examples

C1
UK/ˈflæt.laɪn/US/ˈflæt.laɪn/

Informal, Medical (literal); Journalistic/Figurative (extended)

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Quick answer

What does “flatline” mean?

To show no electrical activity on a heart monitor (electrocardiogram), indicating cardiac arrest and death.

Audio

Pronunciation

Definition

Meaning and Definition

To show no electrical activity on a heart monitor (electrocardiogram), indicating cardiac arrest and death; a state of zero activity or response.

Used figuratively to describe any activity, metric, or signal that has fallen to and remains at zero, indicating failure, death, or complete inactivity (e.g., a company's profits, a TV show's ratings, brain function).

Dialectal Variation

British vs American Usage

Differences

No significant difference in meaning or usage. Both use the term similarly in medical and figurative contexts.

Connotations

In both varieties, the literal medical sense carries grave seriousness. Figuratively, it is vivid and often dramatic.

Frequency

Equally common in both varieties in figurative use. The medical term is standard in both.

Grammar

How to Use “flatline” in a Sentence

Subject (intransitive): The patient flatlined.Subject + Prepositional Phrase: Sales flatlined at zero for months.

Vocabulary

Collocations

strong
heart flatlinesflatline on the monitorbrain activity flatlines
medium
profits flatlineratings flatlinegrowth flatlines
weak
flatline completelyflatline suddenlyflatline for hours

Examples

Examples of “flatline” in a Sentence

verb

British English

  • The patient flatlined at 03:42 hours.
  • Viewer numbers for the programme have flatlined.

American English

  • The show flatlined in the ratings after the first season.
  • His heart flatlined for two minutes before they revived him.

adjective

British English

  • The flatline EEG was a concerning sign.
  • We're looking at flatline growth for the foreseeable future.

American English

  • The stock chart showed a flatline trend.
  • The flatline response from the audience was disheartening.

Usage

Meaning in Context

Business

Profits flatlined this quarter, worrying investors.

Academic

The study's data suggests cognitive function flatlined under the experimental condition.

Everyday

My phone battery flatlined right when I needed the map.

Technical

The patient's ECG showed a flatline, confirming asystole.

Vocabulary

Synonyms of “flatline”

Strong

dieexpirecrashfail completely

Neutral

stopstagnateplateauremain static

Vocabulary

Antonyms of “flatline”

Watch out

Common Mistakes When Using “flatline”

  • Using it as a positive (e.g., 'Our stability flatlined' – incorrect, implies failure).
  • Using it for a temporary dip (it implies sustained zero).
  • Misspelling as two words: 'flat line' (noun is often one word, verb is one word).

FAQ

Frequently Asked Questions

No. While it originated there, its figurative use to mean 'fall to and remain at zero activity' is now very common in business, media, and general language.

Yes. As a noun: 'The monitor showed a flatline.' As a verb (most common): 'The economy flatlined.'

No. 'Stabilise' is neutral or positive, meaning to become steady. 'Flatline' is negative, meaning to become steady at zero or a very low, lifeless level.

The noun form referring to the medical reading is often written as one word ('flatline'), especially in figurative uses. The two-word version 'flat line' is sometimes used literally to describe the visual graph.

To show no electrical activity on a heart monitor (electrocardiogram), indicating cardiac arrest and death.

Flatline is usually informal, medical (literal); journalistic/figurative (extended) in register.

Flatline: in British English it is pronounced /ˈflæt.laɪn/, and in American English it is pronounced /ˈflæt.laɪn/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

  • flatline on the table (medical)
  • flatline in the polls (political)

Learning

Memory Aids

Mnemonic

Imagine a FLAT LINE on a heart monitor screen - it means no ups and downs, no life, no activity.

Conceptual Metaphor

LIFE/ACTIVITY IS A HEARTBEAT (represented by a line on a monitor). DEATH/INACTIVITY IS A FLAT LINE.

Practice

Quiz

Fill in the gap
After the initial hype, public interest in the product completely.
Multiple Choice

In which context is 'flatline' used CORRECTLY?

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