flatline(redirected from flat-lining)
slang To die or come very close to death. The "flat line" in question is a straight, horizontal line on an electrocardiogram or electroencephalogram indicating a lack of heart or brain activity (as opposed to the peaks and valleys displayed as a result of measuring the vital signs of a living person). The patient flatlined and we were unable to resuscitate. Time of death was 18:56.
in. to die. (From the flatness of the line on an EEG monitor when the heart stops.) It appeared that the patient flatlined during the night.