a collection of minute bubbles formed on the surface of a liquid by agitation, fermentation, etc.: foam on a glass of beer.
the froth of perspiration, caused by great exertion, formed on the skin of a horse or other animal.
froth formed from saliva in the mouth, as in epilepsy and rabies.
a thick frothy substance, as shaving cream.
a chemically produced substance that smothers the flames on a burning liquid by forming a layer of minute, stable, heat-resistant bubbles on the liquid's surface.
the layer of bubbles so formed.
a dispersion of gas bubbles in a solid, as foam glass, foam rubber, polyfoam, or foamed metal.
Literary. the sea.
to form or gather foam; emit foam; froth.
to cause to foam.
to cover with foam; apply foam to: to foam a runway before an emergency landing.
to insulate with foam.
to make (plastic, metal, etc.) into a foam.
Idioms about foam
foam at the mouth, to be extremely or uncontrollably angry.
- foam·a·ble, adjective
- foamer, noun
- foam·ing·ly, adverb
- foamless, adjective
- foamlike, adjective
- de·foam, verb (used with object)
- un·foamed, adjective
- un·foam·ing, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use foam in a sentence
Before pumping the tree with carbon dioxide and sealing it with foam cellophane, scientists managed to capture nearly 100 hornets, including two queens.A nest filled with hundreds of ‘murder hornets’ was destroyed ‘just in the nick of time,’ officials say | Teo Armus | November 12, 2020 | Washington Post
Inside a dark room lined with anti-echo foam, the bats sit in a box on a platform.Here’s what bats ‘see’ when they explore the world with sound | Carolyn Wilke | October 29, 2020 | Science News For Students
This Casper Sleep Essential Mattress is 11-inches thick once out of the box, and uses three layers of memory foam to provide the support you need throughout the night.Home and office products that make sure-fire gifts | PopSci Commerce Team | October 8, 2020 | Popular-Science
Also consider sending your mat to a professional if the internal foam is damaged or if you’re just feeling out of your depth.
It has a remarkable effect on sleepers who live with body pain thanks to its soft foam material, and the cover is easily removable for washing.Memory foam mattress toppers that might change your life | PopSci Commerce Team | October 2, 2020 | Popular-Science
Thrown into a foaming red rage by the ending of The Sopranos or Lost or BSG or Mass Effect?How ‘Battlestar Galactica,’ ‘Game of Thrones,’ and FanFiction Conquered Pop Culture | Arthur Chu | May 6, 2014 | THE DAILY BEAST
The haunting video shows apparent victims, including children, convulsing and foaming at the mouth.Six Chilling Moments from Charlie Rose’s Assad Interview (VIDEO) | Ben Teitelbaum | September 9, 2013 | THE DAILY BEAST
I put this cologne in the same category as my Bath & Body Works foaming hand soaps.Eastbound & Down’s Kenny Powers Lists His Favorite Things | Kenny Powers | February 17, 2012 | THE DAILY BEAST
What if Rush Limbaugh and the rest of the foaming right-wing pundit crowd aren't the face of modern conservatism?
When the butter is foaming, lay in a batch of floured codfish chunks in one layer, not crowded.
At the farm-gate they met Dorothy, fresh and blooming as a rose, with a pail in each hand foaming to the brim with milk.The World Before Them | Susanna Moodie
The foaming waves rose in such volume and to so great a height, that they might almost be mistaken for walls.A Woman's Journey Round the World | Ida Pfeiffer
The inevitable fountain was at the end of the room; it was of white stone, and colored lights played upon its foaming column.Ancestors | Gertrude Atherton
They glanced backward, where another wall of foaming water seemed to be curling over the stern, as if about to drop inboard.The Floating Light of the Goodwin Sands | R.M. Ballantyne
On the outermost corner of the structure, overlooking the eddying, foaming bend of the San Juan, rose the isolated tower.Overland | John William De Forest
British Dictionary definitions for foam
a mass of small bubbles of gas formed on the surface of a liquid, such as the froth produced by agitating a solution of soap or detergent in water
frothy saliva sometimes formed in and expelled from the mouth, as in rabies
the frothy sweat of a horse or similar animal
any of a number of light cellular solids made by creating bubbles of gas in the liquid material and solidifying it: used as insulators and in packaging
(as modifier): foam rubber; foam plastic
a colloid consisting of a gas suspended in a liquid
a mixture of chemicals sprayed from a fire extinguisher onto a burning substance to create a stable layer of bubbles which smothers the flames
a poetic word for the sea
to produce or cause to produce foam; froth
(intr) to be very angry (esp in the phrase foam at the mouth)
- foamless, adjective
- foamlike, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for foam
Small, frothy bubbles formed in or on the surface of a liquid, as from fermentation or shaking.
A colloid in which particles of a gas are dispersed throughout a liquid. Compare aerosol emulsion.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.