flatline
verb
flat·line
ˈflat-ˌlīn 
flatlined; flatlining; flatlines
1
a
: to register on an electronic monitor as having no brain waves or heartbeat
b
: die
2
a
: to be in a state of no progress or advancement
b
: to come to an end
flatliner
noun
Examples of flatline in a Sentence
the patient was fading fast, and doctors expected him to flatline before the night was over
Recent Examples on the Web
In other words, while the Democratic brand continued to flatline, the autopsy itself was declared dead in the cradle—this despite DNC officials having conducted more than 300 interviews and Martin having previously called the autopsy a crucial exercise.
—
Mark Leibovich, The Atlantic, 11 Feb. 2026
Meanwhile, the travel sector, often a bellwether for consumer discretionary spending, has flatlined; Transportation Security Administration numbers for January were stagnant, and hotel occupancy rates dipped 1% year over year.
—Nick Lichtenberg, Fortune, 9 Feb. 2026
Neuromodulation is necessary for keeping the brain’s activity level in a functional range, preventing it from either flatlining or erupting in seizures.
—Ingrid Wickelgren, Quanta Magazine, 30 Jan. 2026
Employee engagement has been in decline since 2020 and, over the past two years, has flatlined at 31% of US employees being actively engaged at work.
—Barnaby Lashbrooke, Forbes.com, 30 Jan. 2026
See All Example Sentences for flatline
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Mark Leibovich, The Atlantic, 11 Feb. 2026
Meanwhile, the travel sector, often a bellwether for consumer discretionary spending, has flatlined; Transportation Security Administration numbers for January were stagnant, and hotel occupancy rates dipped 1% year over year.
—Nick Lichtenberg, Fortune, 9 Feb. 2026
Neuromodulation is necessary for keeping the brain’s activity level in a functional range, preventing it from either flatlining or erupting in seizures.
—Ingrid Wickelgren, Quanta Magazine, 30 Jan. 2026
Employee engagement has been in decline since 2020 and, over the past two years, has flatlined at 31% of US employees being actively engaged at work.
—Barnaby Lashbrooke, Forbes.com, 30 Jan. 2026
See All Example Sentences for flatline
Cite this Entry
“Flatline.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/flatline. Accessed 14 Feb. 2026.
Copy CitationMedical Definition
flatline
intransitive verb
flat·line
ˈflat-ˌlīn
flatlined; flatlining
1
: to register on an electronic monitor as having no heartbeat or brain waves : to experience cessation of heart contractions or brain wave activity as indicated by a flat line on a electrocardiogram or electroencephalogram
I flatlined on the operating table, but Dr. Bunsom managed to revive me.—Alison Wright, Yoga Journal
Alison Wright, Yoga JournalHe used to be ill quite a bit as a younger child, and his heart flatlined four times before he was 6.—Ginnie Graham, Tulsa World
Ginnie Graham, Tulsa World2
: die entry 1
But just because death is expected doesn't mean it's any less depressing when the patient finally flatlines.—Phil Taylor, Sports Illustrated
Phil Taylor, Sports IllustratedLove words? Need even more definitions?
Merriam-Webster unabridged
