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.
the sea.
—v.i.
to form or gather foam; emit foam; froth.
—v.t.
to cause to foam.
to cover with foam; apply foam to: to foam a runway before an emergency landing.