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

In the case of an all-foam mattress, a denser bed will last longer and won’t sink in too much. — Yelena Moroz Alpert, Architectural Digest, 14 July 2026

Each chair transforms into a full-size foam mattress that's already stored inside -- no air pumps or extra storage required. — ABC News, 14 July 2026

Verb

Then use either a foaming coil cleaner or a mixture of warm water and dish soap on the coils, making sure to avoid contact with the electrical controls and fan motor. — Sheila Kim, The Spruce, 9 July 2026

Its foaming properties pull dust off your wheels and dissolve it, requiring a simple rinse afterward. — Bestreviews, Chicago Tribune, 16 June 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