billow

1 of 2

noun

bil·​low ˈbi-(ˌ)lō 

1

: wave

especially : a great wave or surge of water

the rolling billows of the sea

2

: a rolling mass (as of flame or smoke) that resembles a high wave

Billows of smoke poured out of the building.

billows of fog

billowy

ˈbi-lə-wē 

adjective

billow

2 of 2

verb

billowed; billowing; billows

intransitive verb

1

: to rise or roll in waves or surges

the billowing sea

2

: to bulge or swell out (as through action of the wind)

billowing clouds

… the flags … billowed out in pride …

—G. B. Oxnam

transitive verb

: to cause to billow

… a field of burning grass billowing thick black clouds of smoke into the sky.

—Donald Windham

Synonyms of billow

Noun

• wave
• swell

Verb

• protrude
• poke
• bulge

Examples of billow in a Sentence

Noun

Billows of smoke poured out of the burning building.

the rolling billows of the sea

Verb

the curtains in the open windows billowed in the summer wind

Recent Examples on the Web

Noun

In the portrait, taken in the last few weeks, black smoke billows behind her as her fuchsia headscarf billows in the wind behind her. —Charlene Gubash, NBC news, 24 Mar. 2026

Chopper 4 captured the huge billows of smoke coming out of his home located at NW 27th Court and 172nd Terrace, with flames billowing through a large hole in the roof. —Abby Dodge, CBS News, 20 Mar. 2026

Verb

Images and video posted online showed moments after the explosion as smoke plumes and flames billowed into the sky. —Thao Nguyen, USA Today, 25 Mar. 2026

In Tel Aviv, a missile with a 220 pound warhead slipped through Israeli defenses and slammed into a street, blowing out the windows of an apartment building and sending smoke billowing. —CBS News, 24 Mar. 2026

Word History

Etymology

Noun and Verb

Old Norse bylgja; akin to Old High German balg bag — more at belly

First Known Use

Noun

1552, in the meaning defined at sense 1

Verb

1592, in the meaning defined at intransitive sense 1

Rhymes for billow

• pillow
• armadillo
• caudillo

Kids Definition

billow

1 of 2 noun

bil·​low ˈbil-ō 

1

: wave entry 2 sense 1

especially : a large wave

2

: a rolling mass like a high wave

billows of smoke

billow

2 of 2 verb

1

: to rise or roll in waves

the billowing ocean

2

: to bulge or swell out

sails billowing in the breeze