flatline
/ˈflætˌlaɪn/
"flatline" is a 8-letter English headword indexed on PlainSpell.
The verdict
“flatline” is an uncommon English word, ranked #62,898 in English word frequency and used as a noun.
- #62,898
- frequency rank, English
- 8
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An asystole; the absence of heart contractions or brain waves.
| Property | Value |
|---|---|
| Headword | flatline |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈflætˌlaɪn/ |
| Letters | 8 |
| Frequency rank | #62,898 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “flatline” sits in English frequency
Spelling & Dictionary Insight
The English entry for flatline is 8 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈflætˌlaɪn/. Corpus data places it at rank #62,898 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 4 distinct senses for this headword, so context determines which meaning a reader should apply.
The misspelling generator found no plausible variants for flatline, since its letter pattern doesn't lend itself to common typo substitutions. This entry stands alone in our confusable dataset, which typically means the spelling is too distinctive to be mistaken for another word.
Etymologically, the entry records: From flat + line. Refers to a continuous straight line (asystole) on an ECG (EKG) or EEG, indicating death. The correct English form is flatline, spelled F-L-A-T-L-I-N-E.
Definition
- 1An asystole; the absence of heart contractions or brain waves.
- 2An asystole; the absence of heart contractions or brain waves.
- 3An unchanging state, as indicated in a graph of a variable over time.
- 4A line that is run low to the water from the rod tip, generally off a release clip of some type.
Etymology
From flat + line. Refers to a continuous straight line (asystole) on an ECG (EKG) or EEG, indicating death.
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
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Using “flatline”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is F-L-A-T-L-I-N-E - every other letter order is a misspelling in standard orthography.
- Say it as /ˈflætˌlaɪn/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Browse more English words and confusable pairs in the same reference. English words
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.