foam

1 of 2

noun

ˈfōm 

1

: a light frothy mass of fine bubbles formed in or on the surface of a liquid or from a liquid: such as

a

: a frothy mass formed in salivating or sweating

b

: a stabilized froth produced chemically or mechanically and used especially in fighting oil fires

c

: a material in a lightweight cellular form resulting from introduction of gas bubbles during manufacture

2

: sea

3

: something resembling foam

foamless

ˈfōm-ləs 

adjective

foam

2 of 2

verb

foamed; foaming; foams

intransitive verb

1

a

: to produce or form foam

b

: to froth at the mouth especially in anger

broadly : to be angry

2

: to gush out in foam

3

: to become covered with or as if with foam

… streets … foaming with life …

—Thomas Wolfe

transitive verb

1

: to cause to foam

specifically : to cause air bubbles to form in

2

: to convert (something, such as a plastic) into a foam

foamable

ˈfō-mə-bəl 

adjective

foamer

ˈfō-mər 

noun

Synonyms of foam

Noun

• surf
• suds
• froth
• spray
• head

Verb

• steam
• storm
• rage
• boil
• burn
• shake

Examples of foam in a Sentence

Noun

As I poured the beer, foam bubbled up in the glass.

The fire extinguisher is filled with foam.

a can of shaving foam

Verb

The soda foamed in the glass.

The mixture will bubble and foam when you add the yeast.

Recent Examples on the Web

Noun

The agency spokesperson says that the anechoic chamber hadn’t been upgraded since 1997 and that its microwave-absorbing foam spires were crumbling. — Eric Niiler, Scientific American, 22 Sep. 2026

Oribe Hair Alchemy Strengthening Shampoo Made without SLS or SLES (chemical detergents that make products foam up, and remove oil and dirt), Oribe’s Hair Alchemy Strengthening Shampoo is built for fragile, breakage-prone hair. — Valeriya Chupinina, Vogue, 22 Sep. 2026

Verb

For the best results, Dyson recommends using toothpaste without foaming agents. — Maryna Holovnova, New Atlas, 16 Sep. 2026

The Nano Foamer works well to foam both dairy milks and alternatives like oat and almond. — Cassie Gill, Condé Nast Traveler, 20 Aug. 2026

Word History

Etymology

Noun

Middle English fome, from Old English fām; akin to Old High German feim foam, Latin spuma foam, pumex pumice

First Known Use

Noun

before the 12th century, in the meaning defined at sense 1

Verb

before the 12th century, in the meaning defined at intransitive sense 1a

Phrases Containing foam

• cell foam
• cellular foam
• closed-cell foam
• foam at the mouth
• foam cell
• foam rubber
• memory foam
• open-cell foam
• plastic foam
• shaving foam

Rhymes for foam

• brome
• chrome
• comb
• combe
• crome
• dome
• gnome
• holm
• loam
• roam
• tome
• acrosome

Kids Definition

foam

1 of 2 noun

ˈfōm 

1

: a light mass of fine bubbles formed in or on a liquid

2

: a mass of fine bubbles formed (as by a horse) in producing saliva or sweating

3

: a long-lasting mass of bubbles produced chemically and used especially in fighting oil fires

4

: a material (as rubber) in a lightweight cellular form resulting from the presence of gas bubbles during manufacture

foamily

ˈfō-mə-lē

adverb

foaminess

ˈfō-mē-nəs

noun

foamy

-mē

adjective

foam

2 of 2 verb

1

: to produce or form foam : froth

2

: to be angry

Medical Definition

foam

noun

ˈfōm 

: a light frothy mass of fine bubbles formed in or on the surface of a liquid

spermicidal foam

foam verb