billow

American  

[bil-oh] / ˈbɪl oʊ /

noun

• billows
  plural

1. a great wave or surge of the sea.

   Synonyms:

   whitecap, roller, comber, breaker, swell

2. any surging mass.

   billows of smoke.

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verb (used without object)

• billows,
  present (3rd person singular)
• billowed,
  past participle,  past
• billowing
  present participle

1. to rise or roll in or like billows; surge.

2. to swell out, puff up, etc., as by the action of wind.

   flags billowing in the breeze.

verb (used with object)

• billows,
  present (3rd person singular)
• billowed,
  past participle,  past
• billowing
  present participle

1. to make rise, surge, swell, or the like.

   A sudden wind billowed the tent alarmingly.

billow British  

/ ˈbɪləʊ /

noun

1. a large sea wave

2. a swelling or surging mass, as of smoke or sound

3. a large atmospheric wave, usually in the lee of a hill

4. poetic (plural) the sea itself

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verb

1. to rise up, swell out, or cause to rise up or swell out

Other Word Forms

Derived Forms

• underbillow
  verb (used without object)
• billowing
  adjective

Inflected Forms

Nouns

• billows
  plural

Participles

• billowing
  present
• billowed
  past

Conjugated Forms

Present

• billow
  simple
• billows
  simple
• have billowed
  perfect
• has billowed
  perfect
• am billowing
  progressive
• are billowing
  progressive
• is billowing
  progressive
• have been billowing
  perfect progressive
• has been billowing
  perfect progressive

Past

• billowed
  simple
• had billowed
  perfect
• was billowing
  progressive
• were billowing
  progressive
• had been billowing
  perfect progressive

Future

• will billow
  simple
• will have billowed
  perfect
• will be billowing
  progressive
• will have been billowing
  perfect progressive

Etymology

Origin of billow

First recorded in 1545–55; from Old Norse bylgja “wave,” cognate with Middle Low German bulge; akin to Old English gebylgan “to anger, provoke”

Explanation

Something billows when there's a fluid or blowing motion, such as the air filling a curtain at an open window, or smoke billowing from a fire. This word originally meant a wave, and that image should help you remember its current meaning too. The word usually suggests movement and growth, such as waves building and crashing. There are certain clouds that look like ocean waves, and so are called billow clouds. If you have a big shirt, the wind might make it fill with air and billow. Balloons are billowed when you inflate them. Billowing can also mean to move with difficulty — slowly.

Example Sentences

See Examples For:

billow billows billowed billowing

Clouds billow and curl; chariots race upward, representing sutras that may deliver you to heaven.

From The Wall Street Journal ● Jul. 31, 2026

Thick clouds of red dust billow skyward as earthmovers cut roads through the Abujhmad hills of India's central Chhattisgarh state, the last holdout of a nearly 60-year insurgency that has cost 12,000 lives.

From Barron's ● Apr. 22, 2026

On the morning of Sept. 11, 2001, I was in northern New Jersey, and watched the smoke billow from the World Trade Center.

From Slate ● Oct. 29, 2025

“I am crossing my fingers, we are OK for now,” said Pavelka as he watched smoke billow over the Santa Ana Mountains near the spot where he has lived for 20 years.

From Los Angeles Times ● Sep. 11, 2024

Once it’s dry, it’ll billow in blond waves.

From "Black Brother, Black Brother" by Jewell Parker Rhodes

"Baptism of fire" is the Observer's headline, accompanied with a picture of a man wading into the ocean as smoke billows from the wildfires in the distance.

From BBC ● Jul. 26, 2026

Sprouting eyes, wings, beaks, the slender monolith seemingly rotates and billows as it rises.

From The Wall Street Journal ● Jul. 1, 2026

AFP journalists who traveled to the landfill site by boat saw billows of thick, gray smoke completely enveloping houses on Salambao -- one of the islands from which people were evacuated.

From Barron's ● Apr. 30, 2026

His TikTok page billows with shortform clips from the crime scene—uploaded thrice-daily from his front-facing camera—offering benign commentary on the languishing investigation.

From Slate ● Feb. 23, 2026

Something about her heart-shaped face, her billows of soft, caramel-colored hair, reminded me of the ingenues of the silent-movie era.

From "Twilight" by Stephenie Meyer

As students patted soil and staked trees for support, smoke from the wind-driven Sandy fire threatening Simi Valley billowed in the distance.

From Los Angeles Times ● May 23, 2026

It was an emotional occasion for fans gathered in the city centre, where claret and blue smoke billowed from flares as flags were flown.

From BBC ● May 21, 2026

I’m not sure what would provoke anyone to tune in, but like clockwork, the viewership billowed to the thousands.

From Slate ● Feb. 23, 2026

As the eruption column billowed into the sky, day turned to night.

From The Wall Street Journal ● Jan. 2, 2026

Before she reached me, an arrow exploded at her feet and a cloud of yellow smoke billowed around her team.

From "The Titan's Curse" by Rick Riordan

Disaster management agency Conred issued a nationwide orange alert, the second highest, and warned locals to be prepared as the eruptions could create further pyroclastic flows and billowing ash clouds.

From BBC ● Aug. 4, 2026

In the distance, she could see the billowing black smoke of a raging fire in nearby Gironde.

From The Wall Street Journal ● Jul. 31, 2026

Columns of thick black smoke were still billowing into the sky from one of the factories hours after the hit, an AFP reporter saw.

From Barron's ● Jul. 24, 2026

But levels of fine particulate matter spiked sharply during the main show, leaving people watching from the south with an obscured view as smoke came billowing their way.

From Barron's ● Jul. 6, 2026

Hundreds of them, dozens of varieties, spiking, trailing, billowing, they dressed the colonnade in a forest of blooms.

From "Strange the Dreamer" by Laini Taylor

Related Words

• undulate