flatline

English

Etymology

From flat +‎ line. Refers to a continuous straight line (asystole) on an ECG (EKG) or EEG, indicating death.

Pronunciation

• IPA^(key): /ˈflætˌlaɪn/

• Audio (AU):

  (file)

Noun

flatline (plural flatlines)

1. An unchanging state, as indicated in a graph of a variable over time.
   • 1967 June 17, "Business Outlook", Business Week, part 6, page 23:

     Thus, you hear words like "flatline recession," "improvement at a greatly reduced rate," "economic hiccup," "recessionette," "rolling readjustment" and "the economy is double clutching."

2. Asystole; the absence of heart contractions or brain waves.
   1. The disappearance of the rhythmic peaks displayed on a heart monitor.
   2. The disappearance of brain waves on an electroencephalogram.
      • 1972, Louis Lasagna, "Aging and the field of medicine", in Aging and Society: Aging and the professions, edited by Matilda White Riley and ‎Anne Foner, page 68:

        When brain function ceases, the electroencephalogram shows flatline recordings.

Verb

1. (intransitive, of the heart) To stop beating.
2. (intransitive, by extension) To die.
3. (transitive, slang) To kill.
   • 2013, Shobha Nihalani, Nine:

     If looks could kill, Mona's sharp gaze would have flatlined him in one second.

   • 2017, Stephanie Rowe, Not Quite Dead:

     After all she'd been through, she needed sleep and food to heal, not endure a lovemaking session that was so passionate that it had pretty much flatlined him as well.

4. To stay at the same level, without development; or, to fall.
   • 2012, The Guardian, National Trust attempts to block £100m Giant's Causeway golf course:

     The economy in Northern Ireland is flatlining and jobs are scarce.