- 1[intransitive] (of a sail, skirt, etc.) to fill with air and swell out The curtains billowed in the breeze.
- 2 [intransitive] if smoke, cloud, etc. billows, it rises and moves in a large mass A huge cloud of smoke billowed out of the chimney.
NAmE//ˈbɪloʊ//Verb Forms present simple I / you / we / they billow
he / she / it billows
past simple billowed
-ing form billowing