- 1[intransitive] balloon (out/up) to suddenly swell out or get bigger Her skirt ballooned out in the wind. Unemployment ballooned to fourteen per cent.
- 2[intransitive] (also go ballooning) to travel in a hot-air balloon as a sport or for entertainment Word Origin late 16th cent. (originally denoting a game played with a large inflated leather ball): from French ballon or Italian ballone
BrE BrE//bəˈluːn//; NAmE NAmE//bəˈluːn//Verb Forms present simple I / you / we / they balloon
BrE BrE//bəˈluːn//; NAmE NAmE//bəˈluːn//he / she / it balloons
BrE BrE//bəˈluːnz//; NAmE NAmE//bəˈluːnz//past simple ballooned
BrE BrE//bəˈluːnd//; NAmE NAmE//bəˈluːnd//past participle ballooned
BrE BrE//bəˈluːnd//; NAmE NAmE//bəˈluːnd//-ing form ballooning
BrE BrE//bəˈluːnɪŋ//; NAmE NAmE//bəˈluːnɪŋ//