- 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.
- (in firefighting)
- 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.
verb (used without object)
- to form or gather foam; emit foam; froth.
verb (used with object)
- 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.
- foam at the mouth, to be extremely or uncontrollably angry.
- 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
- to produce or cause to produce foam; froth
- (intr) to be very angry (esp in the phrase foam at the mouth)
Old English fam “foam, saliva froth,” from West Germanic *faimo- (cf. Old High German veim, German Feim), from PIE *(s)poi-mo-, a root with connotations of “foam, froth” (cf. Sanskrit phenah; Latin pumex “pumice,” spuma “foam;” Old Church Slavonic pena “foam;” Lithuanian spaine “a streak of foam”). The rubber or plastic variety so called from 1937.
Old English famgian “to foam,” from the source of (n.). Related: Foamed; foaming.
- 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.
Be extremely angry, as in She was foaming at the mouth over the judge’s ruling. This hyperbolic term uses the verb foam in the sense of “froth at the mouth,” a usage generally applied to animals such as horses and dating from about a.d. 950. [1400s]