Real Dictionary

froth
uncountable noun: Froth is a mass of small bubbles on the surface of a liquid.
uncountable noun: If you refer to an activity or object as froth, you disapprove of it because it appears exciting or attractive, but has very little real value or importance.
verb: If a liquid froths, small bubbles appear on its surface.
verb: If you say that someone is frothing, or that they are frothing at the mouth, you are emphasizing that they are very angry or excited about something.

froth in American English
a whitish mass of bubbles; foam
to cause to foam
to produce froth; foam
intransitive verb: to give out froth; foam
noun: an aggregation of bubbles, as on an agitated liquid or at the mouth of a hard-driven horse; foam; spume
transitive verb: to cover with froth

froth in British English
noun: a mass of small bubbles of air or a gas in a liquid, produced by fermentation, detergent, etc
verb: to produce or cause to produce froth

froth in Chemical Engineering
noun: A froth is a suspension of a gas in a liquid.