- 1[intransitive] to die
- 2[intransitive] to be at a low level and fail to improve or increase He said the party had been ‘flatlining’—failing to increase its level of support—for eight years. Word Origin 1980s: from flat ‘level’ + line (with reference to the continuous straight line displayed on a heart monitor, indicating death).
BrE BrE//ˈflætlaɪn//; NAmE NAmE//ˈflætlaɪn//(informal)Verb Forms present simple I / you / we / they flatline
BrE BrE//ˈflætlaɪn//; NAmE NAmE//ˈflætlaɪn//he / she / it flatlines
BrE BrE//ˈflætlaɪnz//; NAmE NAmE//ˈflætlaɪnz//past simple flatlined
BrE BrE//ˈflætlaɪnd//; NAmE NAmE//ˈflætlaɪnd//past participle flatlined
BrE BrE//ˈflætlaɪnd//; NAmE NAmE//ˈflætlaɪnd//-ing form flatlining
BrE BrE//ˈflætlaɪnɪŋ//; NAmE NAmE//ˈflætlaɪnɪŋ//