a collection of minute bubbles formed on the surface of a liquid by agitation, fermentation, etc.: foam on a glass of beer.
2.
the froth of perspiration, caused by great exertion, formed on the skin of a horse or other animal.
3.
froth formed from saliva in the mouth, as in epilepsy and rabies.
4.
a thick frothy substance, as shaving cream.
5.
(in firefighting)
a.
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.
O.E. fam "foam, saliva froth," from W.Gmc. *faima (cf. O.H.G. veim, Ger. Feim), from PIE *poim(n)o- (cf. Skt. phenah; L. pumex "pumice," spuma "foam;" O.C.S. pena "foam;" Lith. spaine "a streak of foam"). The verb is from O.E. famgian "to foam." The rubber or plastic variety so called from 1937.
Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition. Copyright 2007. Published by McGraw Hill.
Cite This Source