swell

American  

[swel] / swɛl /

verb (used without object)

swelled, swollen, swelled, swelling

1. to grow in bulk, as by the absorption of moisture or the processes of growth.

   Synonyms:

   expand, distend

   Antonyms:

   contract

2. Pathology. to increase abnormally in size, as by inflation, distention, accumulation of fluids, or the like.

   Her ankles swelled from standing.

3. to rise in waves, as the sea.

4. to well up, as a spring or as tears.

5. to bulge out, as a sail or the middle of a cask.

   Synonyms:

   protrude

6. to grow in amount, degree, force, etc.

7. to increase gradually in volume or intensity, as sound.

   The music swelled.

8. to arise and grow within one, as a feeling or emotion.

9. to become puffed up with pride.

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verb (used with object)

swelled, swollen, swelled, swelling

1. to cause to grow in bulk.

   Synonyms:

   expand, inflate

2. to cause to increase gradually in loudness.

   to swell a musical tone.

3. to cause (a thing) to bulge out or be protuberant.

4. to increase in amount, degree, force, etc.

   Antonyms:

   diminish, decrease

5. to affect with a strong, expansive emotion.

6. to puff up with pride.

noun

1. the act of swelling or the condition of being swollen.

2. inflation or distention.

   Synonyms:

   swelling

3. a protuberant part.

   Synonyms:

   bulge

4. a wave, especially when long and unbroken, or a series of such waves.

   Synonyms:

   billow

5. a gradually rising elevation of the land.

6. an increase in amount, degree, force, etc.

7. a gradual increase in loudness of sound.

8. Music.

   1. a gradual increase (crescendo) followed by a gradual decrease (diminuendo) in loudness or force of musical sound.

   2. the sign (< >) for indicating this.

   3. a device, as in an organ, by which the loudness of tones may be varied.

9. a swelling of emotion within one.

10. Slang.

    1. a fashionably dressed person; dandy.

    2. a socially prominent person.

adjective

Informal.

1. (of things) stylish; elegant.

   a swell hotel.

2. (of persons) fashionably dressed or socially prominent.

   Synonyms:

   grand

3. first-rate; fine.

   a swell party.

   Synonyms:

   grand

swell British  

/ swɛl /

verb

1. to grow or cause to grow in size, esp as a result of internal pressure Compare contract contract

2. to expand or cause to expand at a particular point or above the surrounding level; protrude

3. to grow or cause to grow in size, amount, intensity, or degree

   the party is swelling with new recruits

4. to puff or be puffed up with pride or another emotion

5. (intr) (of seas or lakes) to rise in waves

6. (intr) to well up or overflow

7. (tr) to make (a musical phrase) increase gradually in volume and then diminish

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noun

1. 1. the undulating movement of the surface of the open sea

   2. a succession of waves or a single large wave

2. a swelling or being swollen; expansion

3. an increase in quantity or degree; inflation

4. a bulge; protuberance

5. a gentle hill

6. informal a person very fashionably dressed

7. informal a man of high social or political standing

8. music a crescendo followed by an immediate diminuendo

9. Also called: swell organ.  music

   1. a set of pipes on an organ housed in a box ( swell box ) fitted with a shutter operated by a pedal, which can be opened or closed to control the volume

   2. the manual on an organ controlling this Compare choir great

adjective

1. informal stylish or grand

2. slang excellent; first-class

Other Word Forms

• reswell
  verb
• underswell
  verb (used without object)
• underswell
  noun
• unswelled
  adjective

Etymology

Origin of swell

First recorded before 900; Middle English swellen (verb), Old English swellan; cognate with Dutch zwellen, German schwellen, Old Norse svella; akin to Gothic ufswalleins “pride”

Explanation

To swell is to expand or grow larger. If your brother's face started to swell after he ate lobster for the first time, you'd probably guess that he's allergic to shellfish. You can use the word swell to describe what happens to an injured body part, like a black eye that swells up, or in a figurative way, to describe a feeling of fullness, like when your heart swells with pride at your sister's big music performance. In the 1930s, swell became a popular slang term meaning "great" or "excellent." But it also can describe a wealthy, elegant person, like a group of swells at a fancy restaurant.

Example Sentences

A version of this essay first appeared in The Swell, Salon's culture newsletter.

From Salon • Dec. 13, 2025

Swell sharks depend on kelp to lay their leathery eggs, making them vulnerable to kelp forest loss.

From BBC • Oct. 14, 2025

Irglová exudes a boundless presence in this iteration of the Swell Season.

From Los Angeles Times • Sep. 18, 2025

The company’s first epigenetically grown product, a tomato dubbed Summer Swell, is due to hit shelves this spring.

From Scientific American • May 10, 2023

Swell ladies and gentlemen that Terrance had met on his travels, as well as a newspaperman from London come to report on the American scene.

From "The Underground Railroad: A Novel" by Colson Whitehead

Related Words

• accumulate
• add to
• balloon
• bloat
• bulge
• enlarge
• expand
• fatten
• grow
• increase
• mount
• rise
• surge