foam

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

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

Examples of foam in a Sentence

The soda foamed in the glass.

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

Recent Examples on the Web

The peroxide will foam up and then break down harmlessly into water rather than persisting in your soil. —Brandee Gruener, Southern Living, 9 June 2026

Looking out at an endless expanse of ocean blue while the foaming tide rolls in is enough to put anyone in a vacation state of mind. —Jessica Puckett, Condé Nast Traveler, 5 June 2026

According to Amazon shoppers, one foaming facial cleanser is worth adding to your lineup. —Claire West, PEOPLE, 15 May 2026

The Timberwolves foamed at the mouth, eager to back up Jaden McDaniels’ trash talk about Denver’s defense from three days earlier. —Bennett Durando, Denver Post, 24 Apr. 2026

Word History

First Known Use

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