1. to show no electrical activity on a medical monitor, indicating death or cardiac arrest
Usage: medical
2. to remain at a constant level with no growth or change
Usage: informal

1. a flat horizontal line on a medical monitor indicating no electrical activity
Usage: medical

Examples

• The patient flatlined for two minutes before doctors revived him.
• Her heart monitor showed a flatline.
• Sales have flatlined for the past three quarters.
• The economy flatlined during the recession.
• The stock price flatlined after the announcement.
• The EKG displayed a flatline across the screen.
• His career seemed to flatline after the scandal.